All Stories

  1. Large Magnetic Flux Rope Formation in an X2.1 Flare Observed on 2011 September 6

    Article • The Astrophysical Journal, January 2026, American Astronomical Society

    Dr Keiji Hayashi

  2. A Data-constrained Magnetohydrodynamic Simulation of Successive X-class Flares in Solar Active Region 13842. II. Dynamics of the Solar Eruption Associated with the X9.0 Solar Flare

    Article • The Astrophysical Journal, September 2025, American Astronomical Society

    Dr Keiji Hayashi

  3. Acceleration of Solar Eruptions via Enhanced Torus Instability Driven by Small-scale Flux Emergence

    Article • The Astrophysical Journal Letters, July 2025, American Astronomical Society

    Dr Keiji Hayashi

  4. A Data-constrained Magnetohydrodynamic Simulation of Successive X-class Flares in Solar Active Region 13842. I. Dynamics of the Solar Eruption Associated with the X7.1 Solar Flare

    Article • The Astrophysical Journal, May 2025, American Astronomical Society

    Dr Keiji Hayashi

  5. A Magnetohydrodynamics Simulation of Coronal Mass Ejections in the Upper Corona at 2.5R⊙ ≤ r ≤ 19R⊙

    Article • The Astrophysical Journal, January 2025, American Astronomical Society

    Dr Keiji Hayashi

  6. Are Electric-field-driven Magnetohydrodynamic Simulations of the Solar Corona Sensitive to the Initial Condition?

    Article • The Astrophysical Journal, January 2024, American Astronomical Society

    Dr Keiji Hayashi

  7. Boundary Treatment for the Subsonic/Alfvénic Inner Boundary at 2.5 R ⊙ in a Time-dependent 3D Magnetohydrodynamics Solar Wind Simulation Model

    Article • The Astrophysical Journal Supplement Series, September 2023, American Astronomical Society

    Dr Keiji Hayashi

  8. A new time-dependent three-dimensional magnetohydrodynamics (MHD) simulation model for the trans-sonic/Alfvenic solar wind from 2.5Rs

    Article • May 2023, Copernicus GmbH

    Dr Keiji Hayashi

  9. An Evolution and Eruption of the Coronal Magnetic Field through a Data-driven MHD Simulation

    Article • The Astrophysical Journal, March 2023, American Astronomical Society

    Dr Keiji Hayashi

  10. A Comparative Study of Solar Active Region 12371 with Data-constrained and Data-driven Magnetohydrodynamic Simulations

    Article • The Astrophysical Journal Letters, February 2023, American Astronomical Society

    Dr Keiji Hayashi

  11. The Nonpotentiality of Steady-state Coronal Magnetic Field Derived with Time-relaxation Magnetohydrodynamics Simulations Using Helioseismic and Magnetic Imager Three-component Magnetic Field Data

    Article • The Astrophysical Journal, November 2022, American Astronomical Society

    Dr Keiji Hayashi

  12. An Electric-field-driven Global Coronal Magnetohydrodynamics Simulation Model Using Helioseismic and Magnetic Imager Vector-magnetic-field Synoptic Map Data

    Article • The Astrophysical Journal, May 2022, American Astronomical Society

    Dr Keiji Hayashi

  13. Optimization of parameters of CME initiation in the MHD simulation suite

    Article • March 2022, Copernicus GmbH

    Dr Keiji Hayashi

  14. Coupling a Global Heliospheric Magnetohydrodynamic Model to a Magnetofrictional Model of the Low Corona

    Article • The Astrophysical Journal Supplement Series, April 2021, American Astronomical Society

    Dr Keiji Hayashi

  15. The Coronal Global Evolutionary Model: Using HMI Vector Magnetogram and Doppler Data to Determine Coronal Magnetic Field Evolution

    Article • The Astrophysical Journal Supplement Series, October 2020, American Astronomical Society

    Dr Keiji Hayashi

  16. Comparative Study of Data-driven Solar Coronal Field Models Using a Flux Emergence Simulation as a Ground-truth Data Set

    Article • The Astrophysical Journal, February 2020, American Astronomical Society

    Dr Keiji Hayashi

  17. Parametric Study of ICME Properties Related to Space Weather Disturbances via a Series of Three-Dimensional MHD Simulations

    Article • Solar Physics, October 2019, Springer Science + Business Media

    Dr Keiji Hayashi

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

    Article • The Astrophysical Journal, March 2019, American Astronomical Society

    Dr Keiji Hayashi

  19. Magnetohydrodynamic Simulations for Solar Active Regions using Time-series Data of Surface Plasma Flow and Electric Field Inferred from Helioseismic Magnetic Imager Vector Magnetic Field Measurements

    Article • The Astrophysical Journal Letters, January 2019, American Astronomical Society

    Dr Keiji Hayashi

  20. Prospective White-light Imaging and In Situ Measurements of Quiescent Large-scale Solar-wind Streams from the Parker Solar Probe and Solar Orbiter

    Article • The Astrophysical Journal, December 2018, American Astronomical Society

    Dr Keiji Hayashi

  21. Erratum: “An MHD Simulation of Solar Active Region 11158 Driven with Time-dependent Electric Field Determined from HMI Vector Magnetic Field Measurement Data” (2018, ApJ, 855, 11)

    Article • The Astrophysical Journal, April 2018, American Astronomical Society

    Dr Keiji Hayashi

  22. An MHD Simulation of Solar Active Region 11158 Driven with a Time-dependent Electric Field Determined from HMI Vector Magnetic Field Measurement Data

    Article • The Astrophysical Journal, February 2018, American Astronomical Society

    Dr Keiji Hayashi

  23. Prospective Out-of-ecliptic White-light Imaging of Coronal Mass Ejections Traveling through the Corona and Heliosphere

    Article • The Astrophysical Journal, January 2018, American Astronomical Society

    Dr Keiji Hayashi

  24. Prospective Out-of-ecliptic White-light Imaging of Interplanetary Corotating Interaction Regions at Solar Maximum

    Article • The Astrophysical Journal, July 2017, American Astronomical Society

    Dr Keiji Hayashi

  25. Relation Between Coronal Hole Areas and Solar Wind Speeds Derived from Interplanetary Scintillation Measurements

    Article • Solar Physics, February 2017, Springer Science + Business Media

    Dr Keiji Hayashi

  26. Vector Magnetic Field Synoptic Charts from the Helioseismic and Magnetic Imager (HMI)

    Article • Solar Physics, January 2017, Springer Science + Business Media

    Dr Keiji Hayashi

  27. Exploration of solar photospheric magnetic field data sets using the UCSD tomography

    Article • Space Weather, December 2016, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  28. LONG-TERM TREND OF SOLAR CORONAL HOLE DISTRIBUTION FROM 1975 TO 2014

    Article • The Astrophysical Journal Letters, August 2016, American Astronomical Society

    Dr Keiji Hayashi

  29. MHD-IPS analysis of relationship among solar wind density, temperature, and flow speed

    Article • Journal of Geophysical Research Space Physics, August 2016, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  30. STRUCTURE AND STABILITY OF MAGNETIC FIELDS IN SOLAR ACTIVE REGION 12192 BASED ON NONLINEAR FORCE-FREE FIELD MODELING

    Article • The Astrophysical Journal, February 2016, American Astronomical Society

    Dr Keiji Hayashi

  31. Comparison of potential field solutions for Carrington Rotation 2144

    Article • Journal of Geophysical Research Space Physics, February 2016, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  32. The Coronal Global Evolutionary Model: Using HMI Vector Magnetogram and Doppler Data to Model the Buildup of Free Magnetic Energy in the Solar Corona

    Article • Space Weather, June 2015, American Geophysical Union (AGU)

    Dr George H Fisher, Dr Keiji Hayashi

  33. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Magnetohydrodynamics Simulation Module for the Global Solar Corona

    Article • Solar Physics, April 2015, Springer Science + Business Media

    Dr Keiji Hayashi

  34. MAGNETOHYDRODYNAMIC SIMULATION OF THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15. II. DYNAMICS CONNECTING THE SOLAR FLARE AND THE CORONAL MASS EJECTION

    Article • The Astrophysical Journal, April 2015, Institute of Physics Publishing

    Dr Keiji Hayashi

  35. STATISTICAL ANALYSIS OF THE HORIZONTAL DIVERGENT FLOW IN EMERGING SOLAR ACTIVE REGIONS

    Article • The Astrophysical Journal, September 2014, Institute of Physics Publishing

    Dr Keiji Hayashi

  36. MAGNETOHYDRODYNAMIC SIMULATION OF THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15. I. COMPARISON WITH THE OBSERVATIONS

    Article • The Astrophysical Journal, June 2014, Institute of Physics Publishing

    Dr Keiji Hayashi

  37. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches

    Article • Solar Physics, April 2014, Springer Science + Business Media

    Dr Keiji Hayashi

  38. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance

    Article • Solar Physics, March 2014, Springer Science + Business Media

    Dr Keiji Hayashi

  39. MAGNETIC HELICITY IN EMERGING SOLAR ACTIVE REGIONS

    Article • The Astrophysical Journal, March 2014, Institute of Physics Publishing

    Dr Keiji Hayashi

  40. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Optimization of the Spectral Line Inversion Code

    Article • Solar Physics, March 2014, Springer Science + Business Media

    Dr Keiji Hayashi

  41. MHD analysis of the velocity oscillations in the outer heliosphere

    Article • Geophysical Research Letters, March 2014, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  42. An MHD simulation model of time‐dependent global solar corona with temporally varying solar‐surface magnetic field maps

    Article • Journal of Geophysical Research Space Physics, November 2013, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  43. MAGNETIC STRUCTURE PRODUCING X- AND M-CLASS SOLAR FLARES IN SOLAR ACTIVE REGION 11158

    Article • The Astrophysical Journal, May 2013, Institute of Physics Publishing

    Dr Keiji Hayashi

  44. Properties of High-Frequency Wave Power Halos Around Active Regions: An Analysis of Multi-height Data from HMI and AIA Onboard SDO

    Article • Solar Physics, November 2012, Springer Science + Business Media

    Dr Keiji Hayashi

  45. A NON-RADIAL ERUPTION IN A QUADRUPOLAR MAGNETIC CONFIGURATION WITH A CORONAL NULL

    Article • The Astrophysical Journal, September 2012, Institute of Physics Publishing

    Dr Keiji Hayashi

  46. An MHD simulation model of time-dependent co-rotating solar wind

    Article • Journal of Geophysical Research Atmospheres, August 2012, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  47. DETECTION OF THE HORIZONTAL DIVERGENT FLOW PRIOR TO THE SOLAR FLUX EMERGENCE

    Article • The Astrophysical Journal, May 2012, Institute of Physics Publishing

    Dr Keiji Hayashi

  48. Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager

    Article • Solar Physics, April 2012, Springer Science + Business Media

    Dr Keiji Hayashi

  49. EVOLUTION OF MAGNETIC FIELD AND ENERGY IN A MAJOR ERUPTIVE ACTIVE REGION BASED ONSDO/HMI OBSERVATION

    Article • The Astrophysical Journal, March 2012, Institute of Physics Publishing

    Dr Keiji Hayashi

  50. The MHD simulation of the inner heliosphere over 9 years using the observation-based time-varying boundary data

    Article • January 2012, American Institute of Physics

    Dr Keiji Hayashi

  51. A New Method for Polar Field Interpolation

    Article • Solar Physics, April 2011, Springer Science + Business Media

    Dr Keiji Hayashi

  52. Non‐dipolar solar wind structure observed in the cycle 23/24 minimum

    Article • Geophysical Research Letters, May 2009, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  53. Validation of Two MHD Models of the Solar Corona with Rotational Tomography

    Article • The Astrophysical Journal, August 2008, Institute of Physics Publishing

    Dr Keiji Hayashi

  54. MHD simulations of the global solar corona around the Halloween event in 2003 using the synchronic frame format of the solar photospheric magnetic field

    Article • Journal of Geophysical Research Atmospheres, July 2008, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  55. IPS tomographic observations of 3D solar wind structure

    Article • Astronomical and Astrophysical Transactions, December 2007, Taylor & Francis

    Dr Keiji Hayashi

  56. MHD simulation of two successive interplanetary disturbances driven by cone-model parameters in IPS-based solar wind

    Article • Geophysical Research Letters, October 2006, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  57. The 2003 October–November Fast Halo Coronal Mass Ejections and the Large‐Scale Magnetic Field Structures

    Article • The Astrophysical Journal, April 2006, Institute of Physics Publishing

    Dr Keiji Hayashi

  58. Three-Dimensional Magnetohydrodynamic Simulation of a Global Solar Corona Using a Temperature Distribution Map Obtained fromSOHOEIT Measurements

    Article • The Astrophysical Journal, December 2005, Institute of Physics Publishing

    Dr Keiji Hayashi

  59. Magnetohydrodynamic Simulations of the Solar Corona and Solar Wind Using a Boundary Treatment to Limit Solar Wind Mass Flux

    Article • The Astrophysical Journal Supplement Series, December 2005, Institute of Physics Publishing

    Dr Keiji Hayashi

  60. Fast solar wind after the rapid acceleration

    Article • Journal of Geophysical Research Atmospheres, January 2004, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  61. Polar low-speed solar wind reappeared at the solar activity maximum of cycle 23

    Article • Geophysical Research Letters, April 2003, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  62. MHD tomography using interplanetary scintillation measurement

    Article • Journal of Geophysical Research Atmospheres, March 2003, American Geophysical Union (AGU)

    Dr Keiji Hayashi

  63. How did the solar wind structure change around the solar maximum? From interplanetary scintillation observation

    Article • Annales Geophysicae, January 2003, Copernicus GmbH

    Dr Keiji Hayashi