Updated on 2021/10/27

写真a

 
BAMBA Yumi
 
Organization
Institute for Advanced Research Designated assistant professor
Institute for Space-Earth Environmental Research Designated assistant professor
Title
Designated assistant professor
Contact information
メールアドレス

Degree 1

  1. Ph.D. (Science) ( 2016.3   Nagoya University ) 

Research Interests 8

  1. Space Weather

  2. Sun

  3. Space Weather

  4. Solar Magnetic Field Data Analysis

  5. Solar Physics

  6. Solar Flares

  7. Flare Forecasting

  8. Coronal Mass Ejection

Research Areas 2

  1. Natural Science / Space and planetary sciences  / Interplanetary Physics

  2. Natural Science / Astronomy  / Solar Physics

Research History 3

  1. Daido University   School of Informatics

    2019.4

  2. Nagoya University   Institute for Advanced Reearch   Designated assistant professor

    2019.4

  3. Japan Aerospace Exploration Agency   Institute of Space and Astronautical Science (SOLAR-B Project Team)   Aerospace Project Research Associate

    2016.4 - 2019.3

Education 1

  1. Nagoya University   Graduate School, Division of Natural Science   Division of Particle and Astrophysical Science/Heliospheric and Geospace Physics

    2011.4 - 2016.3

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    Country: Japan

Professional Memberships 3

  1. The Astronomical Society of Japan

  2. Society of Geomagnetism and Earth, Planetary and Space Sciences

  3. JAPAN GEOSCIENCE UNION

Awards 4

  1. Student Outstanding Presentation Award

    2014.5   Japan Geoscience Union  

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    Award type:Award from international society, conference, symposium, etc. 

  2. President Award in Nagoya University Young Women Scientist Meeting

    2013.8   Nagoya University  

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    Award type:Award from Japanese society, conference, symposium, etc. 

  3. Honors in Nagoya University Graduate School of Science

    2013.3   Nagoya University  

  4. President Award

    2013.3   Nagoya University  

 

Papers 18

  1. A physics-based method that can predict imminent large solar flares Reviewed International journal

    Kanya Kusano, Tomoya Iju, Yumi Bamba, Satoshi Inoue

    Science   Vol. 369 ( 6503 ) page: 587 - 591   2020.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science (AAAS)  

    Solar flares are highly energetic events in the Sun’s corona that affect Earth’s space weather. The mechanism that drives the onset of solar flares is unknown, hampering efforts to forecast them, which mostly rely on empirical methods. We present the κ-scheme, a physics-based model to predict large solar flares through a critical condition of magnetohydrodynamic instability, triggered by magnetic reconnection. Analysis of the largest (X-class) flares from 2008 to 2019 (during solar cycle 24) shows that the κ-scheme predicts most imminent large solar flares, with a small number of exceptions for confined flares. We conclude that magnetic twist flux density, close to a magnetic polarity inversion line on the solar surface, determines when and where solar flares may occur and how large they can be.

    DOI: 10.1126/science.aaz2511

    Web of Science

    Scopus

    PubMed

  2. Intrusion of Magnetic Peninsula toward the Neighboring Opposite-polarity Region That Triggers the Largest Solar Flare in Solar Cycle 24 Reviewed International journal

    Yumi Bamba, Satoshi Inoue, Shinsuke Imada

    The Astrophysical Journal   Vol. 894 ( 1 ) page: 29 - 29   2020.5

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    DOI: 10.3847/1538-4357/ab85ca

    Web of Science

    Scopus

    arXiv

    Other Link: https://iopscience.iop.org/article/10.3847/1538-4357/ab85ca

  3. The Role of a Tiny Brightening in a Huge Geoeffective Solar Eruption Leading to the St. Patrick’s Day Storm Reviewed International journal

    Yumi Bamba, Satoshi Inoue, Keiji Hayashi

    The Astrophysical Journal   Vol. 874 ( 1 ) page: 73   2019.3

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    DOI: 10.3847/1538-4357/ab06ff

    Web of Science

    Scopus

  4. Evaluation of Applicability of a Flare Trigger Model Based on a Comparison of Geometric Structures Reviewed International journal

    Yumi Bamba, Kanya Kusano

    Astrophysical Journal   Vol. 856 ( 1 )   2018.3

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    © 2018. The American Astronomical Society. All rights reserved. The triggering mechanism(s) and critical condition(s) of solar flares are still not completely clarified, although various studies have attempted to elucidate them. We have also proposed a theoretical flare-trigger model based on MHD simulations in which two types of small-scale bipole fields, the so-called opposite polarity (OP) and reversed shear (RS), can trigger flares. In this study, we evaluated the applicability of our flare-trigger model to the observation of 32 flares that were observed by the Solar Dynamics Observatory, by focusing on geometrical structures. We classified the events into six types, including the OP and RS types, based on photospheric magnetic field configuration, presence of precursor brightenings, and shape of the initial flare ribbons. As a result, we found that approximately 30% of the flares were consistent with our flare-trigger model, and the number of RS-type triggered flares is larger than that of the OP type. We found that none of the sampled events contradict our flare model; though, we cannot clearly determine the trigger mechanism of 70% of the flares in this study. We carefully investigated the applicability of our flare-trigger model and the possibility that other models can explain the other 70% of the events. Consequently, we concluded that our flare-trigger model has certainly proposed important conditions for flare-triggering.

    DOI: 10.3847/1538-4357/aaacd1

    Web of Science

    Scopus

  5. Study on Precursor Activity of the X1.6 Flare. in the Great AR 12192 with SDO, IRIS, and Hinode Reviewed International coauthorship International journal

    Yumi Bamba, Kyoung-Sun Lee, Shinsuke Imada, Kanya Kusano

    ASTROPHYSICAL JOURNAL   Vol. 840 ( 2 )   2017.5

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    The physical properties and their. contribution to the onset of a solar flare are still uncleare even. though chromospheric brightening is considered a precursor phenomenon of a flare. Many studies suggested that photospheric magnetic field changes cause destabilization of large-scale coronal structure. We aim to understand how a small photospheric change contributes to a flare and to reveal how the intermediary chromosphere behaves in the precursor phase. We analyzed the precursor brightening of the X1.6 flare on 2014 October 22 in the AR 12192 using the Interface Region Imaging Spectrograph (IRIS) and Hinode/EUV Imaging Spectrometer (EIS) data. We investigated a localized jet with the strong precursor brightening, and compared the intensity, Doppler velocity, and line width in C II, Mg II k, and. Si IV lines by IRIS and He II, Fe XII, and. Fe XV lines by Hinode/EIS. We also analyzed the photospheric magnetic field and chromospheric/coronal structures using the. Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly. We found a significant blueshift (similar to 100 km s(-1)), which is related to the strong precursor brightening over a characteristic magnetic field structure, and the blueshift was observed at all of. the temperatures. This might indicate that the flow is accelerated by Lorentz force. Moreover, the large-scale coronal loop that connects the foot points of the flare ribbons was destabilized just after the precursor brightening with the blueshift. It suggests that magnetic reconnection locally occurred in the lower chromosphere and it triggered magnetic reconnection of the X1.6 flare in the corona.

    DOI: 10.3847/1538-4357/aa6dfe

    Web of Science

    Scopus

  6. Triggering Process of the X1.0 Three-ribbon Flare in the Great Active Region NOAA 12192 Reviewed International journal

    Yumi Bamba, Satoshi Inoue, Kanya Kusano, Daikou Shiota

    ASTROPHYSICAL JOURNAL   Vol. 838 ( 2 )   2017.4

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    The solar magnetic field in a flare-producing active region (AR) is much more complicated than theoretical models, which assume a very simple magnetic field structure. The X1.0 flare, which occurred in AR 12192 on 2014 October 25, showed a complicated three-ribbon structure. To clarify the trigger process of the flare and to evaluate the applicability of a simple theoretical model, we analyzed the data from Hinode/Solar Optical Telescope and the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, Atmospheric Imaging Assembly. We investigated the spatio-temporal correlation between the magnetic field structures, especially the non-potentiality of the horizontal field, and the bright structures in the solar atmosphere. As a result, we determined that the western side of the positive polarity, which is intruding on a negative polarity region, is the location where the flare was triggered. This is due to the fact that the sign of the. magnetic shear in that region was opposite that of. the major shear of the AR, and the significant brightenings were observed over the polarity inversion line (PIL) in that region before flare onset. These features are consistent with the recently proposed flare-trigger model that suggests that small reversed shear (RS) magnetic disturbances can trigger solar flares. Moreover, we found that the RS field was located slightly off the flaring PIL, contrary to the theoretical prediction. We discuss the possibility of an extension of the RS model based on an extra numerical simulation. Our result suggests that the RS field has a certain flexibility for displacement from a highly sheared PIL, and that the RS field triggers more flares than we expected.

    DOI: 10.3847/1538-4357/aa6682

    Web of Science

    Scopus

  7. Comparison between Hinode/SOT and SDO/HMI, AIA data for the study of the solar flare trigger process Reviewed International journal

    Bamba Yumi, Kusano Kanya, Imada Shinsuke, Iida Yusuke

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   Vol. 66   2014.12

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:OXFORD UNIVERSITY PRESS  

    Understanding the mechanism that produces solar flares is important not only from the scientific point of view but also for improving space weather predictability. There are numerous observational and computational studies that have attempted to reveal the onset mechanism of solar flares. However, the underlying mechanism of flare onset remains elusive. To elucidate the flare trigger mechanism, we analyzed several flare events which were observed by Hinode/Solar Optical Telescope (SOT) in our previous study. Because of the limitation of the SOT field of view, however, only four events in the Hinode data sets have been usable. Therefore, increasing the number of events is required for evaluating the flare trigger models. We investigated the applicability of data obtained by the Solar Dynamics Observatory (SDO) to increase the data sample for a statistical analysis of the flare trigger process. SDO regularly observes the full disk of the sun and all flares, although its spatial resolution is lower than that of Hinode. We investigated the M6.6 flare which occurred on 2011 February 13, and compared the analyzed data of SDO with the results of our previous study using Hinode/SOT data. Filter and vector magnetograms obtained by the Helioseismic and Magnetic Imager and filtergrams from the Atmospheric Imaging Assembly (AIA) 1600 Å were employed. From the comparison of small-scale magnetic configurations and chromospheric emission prior to the flare onset, we confirmed that the trigger region is detectable with the SDO data. We also measured the magnetic shear angles of the active region and the azimuth and strength of the flare trigger field. The results were consistent with our previous study. We concluded that statistical studies of the flare trigger process are feasible with SDO as well as Hinode data. We also investigated the temporal evolution of the magnetic field before the flare onset with SDO.

    DOI: 10.1093/pasj/psu091

  8. STUDY ON THE TRIGGERING PROCESS OF SOLAR FLARES BASED ON HINODE/SOT OBSERVATIONS Reviewed International journal

    Bamba Y., Kusano K., Yamamoto T. T., Okamoto T. J.

    ASTROPHYSICAL JOURNAL   Vol. 778 ( 1 )   2013.11

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We investigated four major solar flare events that occurred in active regions NOAA 10930 (2006 December 13 and 14) and NOAA 11158 (2011 February 13 and 15) by using data observed by the Solar Optical Telescope on board the Hinode satellite. To reveal the trigger mechanism of solar flares, we analyzed the spatio-temporal correlation between the detailed magnetic field structure and the emission image of the Ca II H line at the central part of flaring regions for several hours prior to the onset of the flares. In all the flare events, we observed that the magnetic shear angle in the flaring regions exceeded 70°, as well as that characteristic magnetic disturbances developed at the centers of flaring regions in the pre-flare phase. These magnetic disturbances can be classified into two groups depending on the structure of their magnetic polarity inversion lines; the so-called opposite-polarity and reversed-shear magnetic field recently proposed by our group, although the magnetic disturbance in one event of the four samples is too subtle to clearly recognize the detailed structure. The result suggests that some major solar flares are triggered by rather small magnetic disturbances. We also show that the critical size of the flare-trigger field varies among flare events and briefly discuss how the flare-trigger process depends on the evolution of active regions.

    DOI: 10.1088/0004-637X/778/1/48

  9. MAGNETIC FIELD STRUCTURES TRIGGERING SOLAR FLARES AND CORONAL MASS EJECTIONS Reviewed International journal

    Kusano K., Bamba Y., Yamamoto T. T., Iida Y., Toriumi S., Asai A.

    ASTROPHYSICAL JOURNAL   Vol. 760 ( 1 )   2012.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    Solar flares and coronal mass ejections, the most catastrophic eruptions in our solar system, have been known to affect terrestrial environments and infrastructure. However, because their triggering mechanism is still not sufficiently understood, our capacity to predict the occurrence of solar eruptions and to forecast space weather is substantially hindered. Even though various models have been proposed to determine the onset of solar eruptions, the types of magnetic structures capable of triggering these eruptions are still unclear. In this study, we solved this problem by systematically surveying the nonlinear dynamics caused by a wide variety of magnetic structures in terms of three-dimensional magnetohydrodynamic simulations. As a result, we determined that two different types of small magnetic structures favor the onset of solar eruptions. These structures, which should appear near the magnetic polarity inversion line (PIL), include magnetic fluxes reversed to the potential component or the nonpotential component of major field on the PIL. In addition, we analyzed two large flares, the X-class flare on 2006 December 13 and the M-class flare on 2011 February 13, using imaging data provided by the Hinode satellite, and we demonstrated that they conform to the simulation predictions. These results suggest that forecasting of solar eruptions is possible with sophisticated observation of a solar magnetic field, although the lead time must be limited by the timescale of changes in the small magnetic structures.

    DOI: 10.1088/0004-637X/760/1/31

  10. An MHD Modeling of the Successive X2.2 and X9.3 Solar Flares of 2017 September 6 Reviewed International journal

    Inoue Satoshi, Bamba Yumi

    ASTROPHYSICAL JOURNAL   Vol. 914 ( 1 )   2021.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Astrophysical Journal  

    The solar active region 12673 produced two successive X-class flares (X2.2 and X9.3) approximately 3 hr apart in 2017 September. The X9.3 flare was the largest recorded solar flare in Solar Cycle 24. In this study we perform a data-constrained magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the initiation and dynamics of the X2.2 and X9.3 flares. According to our simulation, the X2.2 flare is first triggered by magnetic reconnection at a local site where at the photosphere the negative polarity intrudes into the opposite-polarity region. This magnetic reconnection expels the innermost field lines upward, beneath which the magnetic flux rope is formed through continuous reconnection with external twisted field lines. Continuous magnetic reconnection after the X2.2 flare enhances the magnetic flux rope, which is lifted up and eventually erupts via the torus instability. This gives rise to the X9.3 flare.

    DOI: 10.3847/1538-4357/abf835

    Web of Science

    Scopus

  11. Magnetohydrodynamic Modeling of a Solar Eruption Associated with an X9.3 Flare Observed in the Active Region 12673 Reviewed International coauthorship International journal

    Inoue Satoshi, Shiota Daikou, Bamba Yumi, Park Sung-Hong

    ASTROPHYSICAL JOURNAL   Vol. 867 ( 1 )   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3847/1538-4357/aae079

    Web of Science

    Scopus

  12. Onset mechanism of solar eruptions Reviewed International journal

    Satoshi Inoue, Yumi Bamba, Kanya Kusano

    Journal of Atmospheric and Solar-Terrestrial Physics   Vol. 180   page: 3 - 8   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    © 2017 Elsevier Ltd Solar eruptions are the most energetic phenomena observed in the solar system observed as flares, coronal mass ejections (CMEs) and filament/prominence eruption. The helically twisted flux tube is widely thought to be the source and driver of solar eruptions and to carry the plasma into the interplanetary space. Those may eventually reach the magnetosphere and cause strong disturbances of the geomagnetic field. Therefore, the understanding of the onset of solar eruptions is important not only in the framework of solar physics but also for the space weather forecast. In this paper, we report on new insight into the onset mechanism of solar eruptions recently obtained from our new studies. We perform the studies in terms of the observational approach with state-of-the-art solar physics satellites and the numerical one with the latest super computer system. We specified two types of small magnetic perturbations of the photospheric magnetic field. These can enhance the magnetic reconnection in the pre-existing non-potential magnetic field, which produces a large flux tube and then drives the eruption. We further confirmed that this reconnection is a key process for the eruption in our latest data-constrained simulation. We report our latest results and our interpretation of the onset mechanism of solar eruptions.

    DOI: 10.1016/j.jastp.2017.08.035

    Web of Science

    Scopus

  13. A Study of Magnetic Field Characteristics of the Flaring Active Region Based on Nonlinear Force-free Field Extrapolation Reviewed International coauthorship International journal

    Johan Muhamad, Kanya Kusano, Satoshi Inoue, Yumi Bamba

    ASTROPHYSICAL JOURNAL   Vol. 863 ( 2 )   2018.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    Coronal magnetic fields are responsible for the onset of solar flares and solar eruptions. However, the type of magnetic field parameters that can be used to measure the critical condition for a solar eruption is still unclear. As an effort to understand the possible condition for a solar flare, we have examined the nondimensional parameter kappa introduced by Ishiguro & Kusano, which contains information about magnetic twist distribution and magnetic flux in an active region (AR). We introduce a new parameter kappa*, as a proxy for kappa, and we have analyzed the evolution of kappa* during the flaring period of an AR using the nonlinear force-free field extrapolated from the photospheric vector magnetic field data. Using data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, we have calculated kappa* for the AR NOAA 11158 during its three-day flaring period. We found that kappa* increased to a certain level before two large flares and decreased significantly after their onset. The results suggest that kappa* may be used as an indicator of the necessary condition for the onset of a solar eruption in the AR. Based on this result, we propose a new method to assess the possibility of a large solar eruption from an AR by combining the parameter kappa* and information about the magnetic energy of the AR.

    DOI: 10.3847/1538-4357/aad181

    Web of Science

    Scopus

  14. IRIS, Hinode, SDO, and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons Reviewed International coauthorship International journal

    Kyoung-Sun Lee, Shinsuke Imada, Kyoko Watanabe, Yumi Bamba, David H. Brooks

    ASTROPHYSICAL JOURNAL   Vol. 836 ( 2 )   2017.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14: 02 UT and was observed by Hinode, IRIS, SDO, and RHESSI. We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode/ EIS, we measure the temporal variation of the plasma properties in the bright kernel in the chromosphere and corona. We find that explosive evaporation was observed when the WL emission occurred, even though the intensity enhancement in hotter lines is quite weak. The temporal correlation of the WL emission, HXR peak, and evaporation flows indicates that the WL emission was produced by accelerated electrons. To understand the WL emission process, we calculated the energy flux deposited by non-thermal electrons (observed by RHESSI) and compared it to the dissipated energy estimated from a chromospheric line (Mg II triplet) observed by IRIS. The deposited energy flux from the non-thermal electrons is about (3-7.7) x 10(10) erg cm(-2) s(-1) for a given low-energy cutoff of 30-40 keV, assuming the thick-target model. The energy flux estimated from the changes in temperature in the chromosphere measured using the Mg II subordinate line is about (4.6-6.7) x 10(9) erg cm(-2) s(-1): similar to 6%-22% of the deposited energy. This comparison of estimated energy fluxes implies that the continuum enhancement was directly produced by the non-thermal electrons.

    DOI: 10.3847/1538-4357/aa5b8b

    Web of Science

    Scopus

  15. High-speed photospheric material flow observed at the polarity inversion line of a delta-type sunspot producing an X5.4 flare on 2012 March 7 Reviewed International coauthorship International journal

    Shimizu Toshifumi, Lites Bruce W., Bamba Yumi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   Vol. 66   2014.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:OXFORD UNIVERSITY PRESS  

    Solar flares abruptly release the free energy stored as a non-potential magnetic field in the corona and may be accompanied by eruptions of the coronal plasma. Formation of a non-potential magnetic field and the mechanisms for triggering the onset of flares are still poorly understood. In particular, photospheric dynamics observed near those polarity inversion lines that are sites of major flare production have not been well observed with high spatial resolution spectro-polarimetry. This paper reports on a remarkable high-speed material flow observed along the polarity inversion line located between flare ribbons at the main energy release side of an X5.4 flare on 2012 March 7. Observations were carried out by the spectro-polarimeter of the Solar Optical Telescope on board Hinode. The high-speed material flow was observed in the horizontally oriented magnetic field formed nearly parallel to the polarity inversion line. This flow persisted from at least six hours before the onset of the flare, and continued for at least several hours after the onset of the flare. Observations suggest that the observed material flow represents neither the emergence nor convergence of the magnetic flux. Rather, it may be considered to be material flow working both to increase the magnetic shear along the polarity inversion line and to develop magnetic structures favorable for the onset of the eruptive flare.

    DOI: 10.1093/pasj/psu089

  16. Coronal behavior before the large flare onset Reviewed International coauthorship International journal

    Imada Shinsuke, Bamba Yumi, Kusano Kanya

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   Vol. 66   2014.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:OXFORD UNIVERSITY PRESS  

    Flares are a major explosive event in our solar system. They are often followed by a coronal mass ejection that has the potential to trigger geomagnetic storms. There are various studies aiming to predict when and where the flares are likely to occur. Most of these studies mainly discuss the photospheric and chromospheric activity before the flare onset. In this paper we study the coronal features before the famous large flare occurrence on 2006 December 13. Using the data from Hinode/Extreme ultraviolet Imaging Spectrometer (EIS), X-Ray Telescope (XRT), and Solar and Heliospheric Observatory (SOHO)/Extreme ultraviolet Imaging Telescope (EIT), we discuss the coronal features in the large scale (a few 100″) before the flare onset. Our findings are as follows. (1) The upflows in and around the active region start growing from ∼ 10 to 30 km s-1 a day before the flare. (2) The expanding coronal loops are clearly observed a few hours before the flare. (3) Soft X-ray and extreme ultraviolet intensity are gradually reduced. (4) The upflows are further enhanced after the flare. From these observed signatures, we conclude that the outer part of active region loops with low density was expanding a day before the flare onset, and the inner part with high density was expanding a few hours before the onset.

    DOI: 10.1093/pasj/psu092

  17. Formation of a Flare-Productive Active Region: Observation and Numerical Simulation of NOAA AR 11158 Reviewed International journal

    Toriumi S., Iida Y., Kusano K., Bamba Y., Imada S.

    SOLAR PHYSICS   Vol. 289 ( 9 ) page: 3351 - 3369   2014.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer  

    We present a comparison of the Solar Dynamics Observatory (SDO) analysis of NOAA Active Region (AR) 11158 and numerical simulations of flux-tube emergence, aiming to investigate the formation process of this flare-productive AR. First, we use SDO/ Helioseismic and Magnetic Imager (HMI) magnetograms to investigate the photospheric evolution and Atmospheric Imaging Assembly (AIA) data to analyze the relevant coronal structures. Key features of this quadrupolar region are a long sheared polarity inversion line (PIL) in the central δ-sunspots and a coronal arcade above the PIL. We find that these features are responsible for the production of intense flares, including an X2.2-class event. Based on the observations, we then propose two possible models for the creation of AR 11158 and conduct flux-emergence simulations of the two cases to reproduce this AR. Case 1 is the emergence of a single flux tube, which is split into two in the convection zone and emerges at two locations, while Case 2 is the emergence of two isolated but neighboring tubes. We find that, in Case 1, a sheared PIL and a coronal arcade are created in the middle of the region, which agrees with the AR 11158 observation. However, Case 2 never builds a clear PIL, which deviates from the observation. Therefore, we conclude that the flare-productive AR 11158 is, between the two cases, more likely to be created from a single split emerging flux than from two independent flux bundles.

    DOI: 10.1007/s11207-014-0502-1

  18. THE MAGNETIC SYSTEMS TRIGGERING THE M6.6 CLASS SOLAR FLARE IN NOAA ACTIVE REGION 11158 Reviewed International journal

    Toriumi Shin, Iida Yusuke, Bamba Yumi, Kusano Kanya, Imada Shinsuke, Inoue Satoshi

    ASTROPHYSICAL JOURNAL   Vol. 773 ( 2 )   2013.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We report a detailed event analysis of the M6.6 class flare in the active region (AR) NOAA 11158 on 2011 February 13. AR 11158, which consisted of two major emerging bipoles, showed prominent activity including one X- and several M-class flares. In order to investigate the magnetic structures related to the M6.6 event, particularly the formation process of a flare-triggering magnetic region, we analyzed multiple spacecraft observations and numerical results of a flare simulation. We observed that, in the center of this quadrupolar AR, a highly sheared polarity inversion line (PIL) was formed through proper motions of the major magnetic elements, which built a sheared coronal arcade lying over the PIL. The observations lend support to the interpretation that the target flare was triggered by a localized magnetic region that had an intrusive structure, namely, a positive polarity penetrating into a negative counterpart. The geometrical relationship between the sheared coronal arcade and the triggering region is consistent with the theoretical flare model based on the previous numerical study. We found that the formation of the trigger region was due to the continuous accumulation of small-scale magnetic patches. A few hours before the flare occurred, the series of emerged/advected patches reconnected with a pre-existing field. Finally, the abrupt flare eruption of the M6.6 event started around 17:30 UT. Our analysis suggests that in the process of triggering flare activity, all magnetic systems on multiple scales are included, not only the entire AR evolution but also the fine magnetic elements.

    DOI: 10.1088/0004-637X/773/2/128

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Books 1

  1. First Ten Years of Hinode Solar On-Orbit Observatory International journal

    Yumi BAMBA( Role: Contributor ,  New Approach to Solar Flare Trigger Process with Hinode/Solar Optical Telescope)

    Springer  2018 

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    Total pages:305   Responsible for pages:125-134   Language:English Book type:Scholarly book

Presentations 11

  1. How to trigger the solar flares? Invited International conference

    Yumi Bamba

    Japan Geoscience Union Meeting 

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    Event date: 2021.5 - 2021.6

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:online   Country:Japan  

  2. Physics-based prediction of imminent giant solar flares International conference

    Kanya Kusano, Tomoya Iju, Yumi Bamba, Satoshi Inoue

    PSTEP-4 

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    Event date: 2020.1

    Language:English   Presentation type:Poster presentation  

    Venue:Aichi, Japan   Country:Japan  

  3. Intrusion of a Magnetic Peninsula Toward Neighboring Opposite Polarity that Triggers the Largest Solar Flare in Solar Cycle 24 International conference

    Yumi Bamba, Satoshi Inoue, Shinsuke Imada

    PSTEP-4 

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    Event date: 2020.1

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  4. Did AR12673 Possibly Produce a Large Solar Eruption Before September 6th 2017? International conference

    Satoshi Inoue, Daiki Yamasaki, Yumi Bamba

    PSTEP-4 

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    Event date: 2020.1

    Language:English   Presentation type:Poster presentation  

    Venue:Aichi, Japan   Country:Japan  

  5. International Actions of the Project for Solar-Terrestrial Environment Prediction (PSTEP) in Japan International conference

    Kanya Kusano, Tomoya Iju, Yumi Bamba, Satoshi Inoue

    American Geoscience Union Meeting 

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    Event date: 2019.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:California, USA   Country:Japan  

  6. An MHD Modeling of the initiation and Dynamics of the X9.3 Flare Observed in September 2017 International conference

    Satoshi Inoue, Yumi Bamba

    Hinode-13/IPELS 

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    Event date: 2019.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Tokyo, Japan   Country:Japan  

  7. Predictability of Solar Flares Based on Satellite Observations and Magnetohydrodynamic Instability Models Invited International conference

    Kanya Kusano, Yumi Bamba, Tomoya Iju, Satoshi Inoue

    Hinode-13/IPELS 

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    Event date: 2019.9

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Tokyo, Japan   Country:Japan  

  8. The Role of a Tiny Brightening in a Huge Geo-effective Solar Eruption Leading to the St Patrick's Day Storm International conference

    Yumi Bamba, Satoshi Inoue, Keiji Hayashi

    Japan Geoscience Union Meeting 

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    Event date: 2019.5

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Chiba, Japan   Country:Japan  

  9. Study on the predictability of imminent giant solar flares based on the theory of double-arc instability International conference

    Kanya Kusano, Tomoya Iju, Yumi Bamba

    Japan Geoscience Union Meeting 

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    Event date: 2019.5

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Chiba, Japan   Country:Japan  

  10. サイクル24最大の太陽フレア発生過程 Invited International conference

    伴場由美、井上諭、今田晋亮、草野完也

    日本地球惑星科学連合大会 

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    Event date: 2019.5

    Language:English   Presentation type:Poster presentation  

    Venue:千葉, 日本   Country:Japan  

  11. Study on the predictability of imminent giant solar flares based on the analysis of triggered instability Invited International conference

    Kanya Kusano, Tomoya Iju, Yumi Bamba

    European Geosciences Union General Assembly 

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    Event date: 2019.4

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Vienna, Austria   Country:Japan  

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KAKENHI (Grants-in-Aid for Scientific Research) 3

  1. 地磁気擾乱を引き起こす磁気フラックスロープの伝搬過程の研究

    Grant number:21K20379  2021.8 - 2023.3

    科学研究費助成事業  研究活動スタート支援

    伴場 由美

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    Authorship:Principal investigator 

    Grant amount:\2600000 ( Direct Cost: \2000000 、 Indirect Cost:\600000 )

  2. Statistical Study for Understanding and Prediction of Solar Explosive and Eruptive Phenomena

    Grant number:16H07478  2016.8 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Research Activity Start-up

    Bamba Yumi

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2990000 ( Direct Cost: \2300000 、 Indirect Cost:\690000 )

    We aim to decide parameters for prediction of solar explosive and eruptive events based on understanding of physical processes. We performed observational verification of theoretical models and statistical data analysis for solar flares observed by the Hinode and SDO satellites. We quantitatively confirmed the physical processes and occurrence conditions of solar flare. Moreover, we proposed new candidates of parameters that would be useful for flare prediction, and discussed universality of our flare trigger model and its parameters.

  3. 衛星観測に基づく太陽フレアのトリガ機構解明とその発生予測に関する研究

    Grant number:15J10092  2015.4 - 2017.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    伴場 由美

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1700000 ( Direct Cost: \1700000 )

 

Teaching Experience (Off-campus) 3

  1. 基礎物理A

    2021.9 - 2022.3 Daido University)

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    Level:Undergraduate (liberal arts)  Country:Japan

  2. 力学(情報学部)

    2021.4 - 2021.8 Daido University)

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    Level:Undergraduate (liberal arts)  Country:Japan

  3. 力学(情報学部)

    2019.4 - 2019.8 Daido University)

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    Level:Undergraduate (liberal arts)  Country:Japan

 

Social Contribution 12

  1. 物理学に基づく方法により差し迫った巨大太陽フレアを予測することが可能に

    Role(s):Media coverage, Informant

    American Association for the Advancement of Science  サイエンス誌に載った日本人研究者  2021.3

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    Audience: College students, Graduate students, Teachers, Guardians, Researchesrs, General, Scientific, Company, Civic organization, Governmental agency, Media

    Type:Newspaper, magazine

  2. 太陽フレアと宇宙天気

    Role(s):Appearance, Lecturer

    (株)アストロラーべ, そば酒庵 寿々屋  酒と宇宙と…  2018.9

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    Audience: College students, Graduate students, General

    Type:Science cafe

  3. サイエンティスト・クエスト

    Role(s):Appearance, Panelist, Lecturer

    日本科学未来館  サイエンティスト・クエスト  日本科学未来館  2017.7

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    Audience: Infants, Schoolchildren, Junior students, High school students, College students, Graduate students, Teachers, Guardians, General

    Type:Science cafe

  4. Solar images seen from Hinode

    Role(s):Appearance

    Japan Geoscience Union, JAXA, NASA  NASA/JAXA Hyperwall Presentation  Makuhari Messe  2017.5

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    Audience: Junior students, High school students, College students, Graduate students, Teachers, Researchesrs, Scientific, Company, Governmental agency, Media

    Type:Lecture

  5. 太陽観測衛星「ひので」による太陽フレア研究最前線

    Role(s):Lecturer

    神奈川IBMユーザー研究会  新春例会 (賀詞交換会) 特別講演  2017.1

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    Audience: General, Company, Governmental agency

    Type:Lecture

  6. 「ひので」/可視光磁場望遠鏡で迫る太陽フレア発生過程の謎

    Role(s):Contribution

    日本天文学会  天文月報 第109巻9月号  2016.9

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    Audience: College students, Graduate students, Teachers, Researchesrs, General, Scientific, Company, Civic organization, Governmental agency

    Type:Promotional material

  7. Solar images seen from Hinode

    Role(s):Appearance

    Japan Geoscience Union, JAXA, NASA  NASA/JAXA Hyperwall Presentation  Makuhari Messe  2016.5

  8. 「宇宙天気予報」は日本にお任せ!ー太陽観測最前線

    Role(s):Media coverage, Informant

    三菱電機  三菱電機サイエンスサイト DSPACE「読む宇宙旅行」  2015.1

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    Audience: Schoolchildren, Junior students, High school students, College students, Graduate students, Teachers, Guardians, General, Company, Media

    Type:Internet

  9. ひので・SDO衛星がとらえたフレアトリガ磁場構造

    Role(s):Appearance, Lecturer

    宇宙航空研究開発機構  JAXA記者勉強会  JAXA東京事務所  2015.1

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    Audience: General, Company, Governmental agency, Media

    Type:Lecture

  10. 晴れのちフレア!?〜太陽フレアの発生は予測できるか?〜

    Role(s):Appearance, Lecturer

    科学技術館  科学ライブショー「ユニバース」  科学技術館  2014.11

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    Audience: Infants, Schoolchildren, Junior students, High school students, College students, Graduate students, Guardians, General

    Type:Science cafe

  11. あかりんご隊科学実験「サイエンスクラフトで遊ぼう☆」

    Role(s):Advisor, Organizing member, Demonstrator

    名古屋大学  ホームカミングデイ  名古屋大学  2013.10

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    Audience: Infants, Schoolchildren, Guardians

    Type:Seminar, workshop

  12. あかりんご隊科学実験「3Dの絵を描こう☆」

    Role(s):Advisor, Organizing member, Demonstrator

    名古屋大学  ホームカミングデイ  名古屋大学  2012.10

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    Audience: Infants, Schoolchildren, Guardians

    Type:Seminar, workshop

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Media Coverage 12

  1. 太陽フレア予測に新手法 Newspaper, magazine

    日本経済新聞  日本経済新聞  2020.8

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    Author:Other 

  2. 太陽フレアを予測する画期的な計算方法 Newspaper, magazine

    アストロアーツ  アストロアーツ  2020.8

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    Author:Other 

  3. 太陽フレアを高精度に予測、名古屋大など開発...9回中7回発生場所まで的中 Newspaper, magazine

    読売新聞  Yahooニュース  2020.8

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    Author:Other 

  4. 太陽フレア予測の新手法 発生条件を解明、名古屋大 Newspaper, magazine

    一般社団法人共同通信社  共同通信ニュース  2020.7

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    Author:Other 

  5. We can now predict dangerous solar flares a day before they happen Newspaper, magazine

    New Scientist  New Scientist  2020.7

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    Author:Other 

  6. SOLAR FLARES Predicting the Sun's brightest flashes Newspaper, magazine

    サイエンス誌  サイエンス誌  2020.7

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    Author:Other 

  7. 巨大太陽フレアを高精度予測 名古屋大などが技術開発 Newspaper, magazine

    産経新聞  産経ニュース  2020.7

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    Author:Other 

  8. 9回中7回的中名大など新手法 Newspaper, magazine

    朝日新聞  朝日新聞デジタル  2020.7

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    Author:Other 

  9. 太陽フレア発生を予測する数式開発 大規模停電など回避へ光 名古屋大 Newspaper, magazine

    毎日新聞  毎日新聞ニュースサイト  2020.7

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    Author:Other 

  10. New Analysis Method Predicts Disruptive Solar Flares Newspaper, magazine

    American Institute of Physics  2020 American Institute of Physics  2020.7

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    Author:Other 

  11. Astronomers develop new method for predicting explosive solar flares Newspaper, magazine

    Astronomy magazine  Astronomy  2020.7

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    Author:Other 

  12. 太陽嵐の脅威に備えろ! TV or radio program

    NHK  コズミックフロント  2013.3

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    Author:Other 

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