Download presentation
Presentation is loading. Please wait.
1
CISM Radiation Belt Models CMIT Mary Hudson CISM Seminar Nov 06
2
Van Allen Radiation Belts inner belt outer belt Slot region
3
Van Allen Belts-Plasmasphere Overlap Ring current
4
Solar Cycle Dependence of 2-6 MeV Electrons Li et al., GRL, 2006
5
Van Allen Radiation Belts: Slot region variability inner belt outer belt Slot region SAMPEX electrons: 2 - 6 MeV slot region L = 2 - 3 Outer belt inner belt
6
slot region new belt Effect on the Radiation Belts [Baker et al., 2004, Nature]
8
March 91 Shock Acceleration 3.5 MeV at L=6.6, t=0 (M =11,150 MeV/G) Elkington et al., JASTP, 02; 04
9
MHD-Guiding Center Simulation Elkington et al., JASTP, 2002; 2004
10
SAMPEX >10 MeV Electron Injections
11
SAMPEX: Mar 91 decay+Feb 94 injection
12
Halloween 03 >10 MeV Electron Injections
13
Global LFM-MHD Simulations of Magnetosphere Solar wind measurements made WIND, ACE or IMP8 (Feb 94, not Mar 91) Solar wind measurements made WIND, ACE or IMP8 (Feb 94, not Mar 91) Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere
14
1994 Feb 21 Event: density
15
1994 Feb 21 Event: E phi
16
Halloween ’03 Shock Injection initial E ~ 5 MeV, R ~ 6 RE, final E ~15 MeV, R ~ 2.5 RE Kress et al., 06
17
Halloween ’03 Shock Injection of >10 MeV (W0=1-7 MeV) Electrons
18
E_phi (left) and Solar Energetic Electron Trajectory (right) Halloween ‘03 solar energetic electron injection event Kress et al., 2006
19
Low altitude SAMPEX observations of > 10 MeV electrons, injected 10/29/03 Low altitude SAMPEX observations of > 10 MeV electrons, injected 10/29/03 E -1.5 electron energy spectrum from several MeV to > 15 MeV Initially not observed at SAMPEX due to eq injection Simulated pitch angle distribution->
20
Outer Belt Losses Due to Whistler Pitch Angle Scattering Hiss Whistler Mode outer belt 2-6 MeV Slot Variability: [Lyons et al., 1972]
21
Losses due to Pitch Angle Scattering VLF waves from p’sheet electrons EMIC waves from ring current ions
22
MHD Fields Injection of RadBelt Electrons Elkington et al., JASTP, 2004
23
MHD Fields Injection of RadBelt Electrons Elkington et al., JASTP, 2004
24
Diffusion Rates vs. L Radial diffusion rates in model ULF wave fields D_LL ~ L N Perry et al., JGR, 05, includes δEφ, δBr, δB//, freq and L-dependent power Braughtigam & Albert, 2000, N=6, 10; Perry et al., 2006, N=6, 12 Radial diffusion rates in model ULF wave fields D_LL ~ L^N Perry et al., JGR, 2005, Include δEφ, δBr, δB//, freq and L-dependence 3D trajectories N ~ 6 for no L-dep power, N ~ 12 with L dependence M=273 MeV/G M=273 MeV/G Tau(L,E) Summers 04 # # Selesnick & Blake 2000 # # # Elkington et al., 2003
25
Solutions to diffusion equation using DLL from model ULF wave fields & and PSD from CRRES measurements in subsequent 10-hr orbits to update inner and outer boundaries Dashed lines show CRRES measurements of PSD 61 days apart. Loss model based on Summers et al. 2004. Perry et al. 2005 DLL=10-2(L/4)^12 day-1
26
MHD-Driven Phase Space Density AE8 Max-Initialized, Sept 98 StormFei et al., 2006 MHD-Test Particle Radial Diffusion
27
New belt example: 24 Nov 2001 Clear trapping of solar particles: 13 of 26 SEP penetration events inside L=4, 98-03 Mazur et al., AGU Monograph 165, 2006
30
Conclusions Drift time scale injection of multi- MeV electrons: Strong compression of dayside magnetopause due to high speed CME Drift time scale injection of multi- MeV electrons: Strong compression of dayside magnetopause due to high speed CME Relativistic electron seed population at and beyond geosynchronous required Relativistic electron seed population at and beyond geosynchronous required Plasmasphere plays role intensifying E_phi Plasmasphere plays role intensifying E_phi Long-lived, energetic trapped population injected into slot region Long-lived, energetic trapped population injected into slot region Well-described by CMIT without coupled RCM Well-described by CMIT without coupled RCM Intermediate storm timescale (hrs,days): changes in PSD described by radial diffusion & loss due to whistler (and EMIC) scattering Intermediate storm timescale (hrs,days): changes in PSD described by radial diffusion & loss due to whistler (and EMIC) scattering Enhanced D_LL due to ULF waves needs further study with RCM coupled to CMIT, plasmasphere, ion outflow to populate m’sphere during IMF Bz<0 Enhanced D_LL due to ULF waves needs further study with RCM coupled to CMIT, plasmasphere, ion outflow to populate m’sphere during IMF Bz<0
31
Drift Time Scale Injection from SSC’s Drift Time Scale Injection from SSC’s Blake et al., 2005
32
Mar 91-Feb 91Comparison
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.