Simulation of Prompt Acceleration of Radiation Belt Electrons During the 16 July 2017 Storm

Abstract

We investigate the prompt enhancement of radiation belt electron flux observed by the Relativistic Electron Proton Telescope instrument on board Van Allen Probes following the 16 July 2017 CME‐shock compression using MHD‐test particle simulations. The prompt enhancements can be explained by the source population interacting with the azimuthally directed electric field impulses induced by CME‐shock compressions of the dayside magnetopause. Electrons in drift resonance with the electric field impulse were accelerated by ∼ 0.6 MeV on a drift period timescale (in minutes) as the impulse propagated from the dayside to the nightside around the flanks of the magnetosphere. MHD test particle simulation of energization and drift phase bunching, due to the bipolar electric field that accompanies the dayside compression and relaxation, is found to be consistent with Van Allen Probes observations. This study reproduces the energy‐dependent drift echoes integrated over pitch angle and observed change in spectra for the first time.

MHD‐Test Particles Simulations of Moderate CME and CIR‐Driven Geomagnetic Storms at Solar Minimum

“…However, the overall radial profile evolution of both events is well captured, with decrease in the initial trapped population dominating the CME‐shock driven storm during main phase and increase in PSD due to the injected population dominating the CIR‐driven storm. MHD‐test particle simulations have also captured well CME‐shock driven prompt injection events such as March 17, 2015 (Hudson et al., 2017) and July 16, 2017 (Patel et al., 2019), wherein a stronger CME‐shock produces a coherent magnetosonic wave disturbance inside the magnetosphere with an azimuthal electric field transporting trapped MeV electrons inward ahead of the magnetopause compression (Hudson et al., 2020 reviews this type of event; Li et al., 1993). For the weaker CME‐shock event studied May 13–14, 2019, magnetopause loss is the dominant early signature of the event with no evidence of prompt injection in the REPT data.…”

ULF Wave Modeling, Effects, and Applications: Accomplishments, Recent Advances, and Future

“…ULF waves in the magnetosphere are studied using coupled global magnetospheric models (e.g., Claudepierre et al, 2008;Hartinger et al, 2014;Claudepierre et al, 2016;Komar et al, 2017) and in simplified field geometries to isolate and better understand underlying physics (Xia et al, 2017;Denton, 2018;Elsden and Wright, 2020;Lysak et al, 2020). Examples of simulations of ULF waves in the magnetosphere presented at GEM UMEA sessions include studies of: global magnetospheric ULF wave modes (Claudepierre et al, 2010;Elsden et al, 2016;Wright, 2017, 2020;Xia et al, 2017;Lysak et al, 2020), magnetospheric ULF wave propagation (Degeling et al, 2018), growth and propagation of EMIC waves (Denton et al, 2014), magnetopause surface waves (Lin et al, 2017;Archer et al, 2021), and interaction of ULF waves with ring current and radiation belt particle populations (Komar et al, 2017;Denton et al, 2019;Patel et al, 2019).…”

Validation of the use of THEMIS-B and THEMIS-C as a near-Earth solar wind monitor

“…This may further drive a geomagnetic storm in the Earth's magnetosphere (Borovsky and Denton, 2006;Shen XC et al, 2017). The energy from the solar wind may be transferred into the Earth's magnetosphere in several ways, such as through ultralow-frequency (ULF) wave excitations (Zhang XY et al, 2010;Liu WL et al, 2013Shen XC et al, 2015;Wang CR et al, 2015;Korotova et al, 2018;Zhang DJ et al, 2020), the acceleration and transport enhancement of energetic particles (Li XL et al, 1993;Zong QG et al, 2009;Foster et al, 2015;Kanekal et al, 2016;Liu ZY et al, 2017;Liu Y et al, 2019;Patel et al, 2019;Xiong Y et al, 2021;Tang CL et al, 2022), and the aurora in the polar region (Zhou XY and Tsurutani, 1999;Zhou XY et al, 2017;Zhu MH et al, 2022).…”