ULF Wave Modelling With A Motive: Effects on Energetic Paritcles Mary Hudson, Scot Elkington, Brian Kress, Kara Perry, John Lyon, Mike Wiltberger

ULF Wave-Relativistic Electron Correlation Rostoker et al., GRL, 1998

Toroidal and Polodial Modes

Hughes, Solar Wind Sources of Magnetospheric ULF Waves, AGU, 1994

CRRES Poloidal and Toriodal ULF Wave B Components CRRES 18 degree inclination, 6.3 RE apogee, July 90 – Oct 91 Hudson et al., Annales. Geophys., 2004

CRRES Occurrence Rates of Poloidal and Toroidal ULF Waves Hudson et al., Annales Geophys., 2004

AMPTE CCE Occurrence Rates Of Toroidal Mode 9 RE apogee Takahashi et al., JGR, 2002

AMPTE IRM Occurrence Rates Of Poloidal/Compressional Mode Anderson et al., JGR 1990

Groundbased Magnetometer ULF Wave Studies Mathie & Mann 2000 JGR Mathie & Mann JGR 2000

Pc5 Correlation with Solar Wind Speed and Relativistic Electrons Mann et al., JASTP, 2004

Convective Growth of Magnetopause K-H Waves Miura, JGR, 1992

Direct Coupling of Solar Wind ULF Waves Kepko et al., GRL, 2002

Transmitting ULF Wave Power Into Magnetosphere via Fast Mode

Structure of Externally Driven FLRs Linear dipole MHD simulation δv ~ δE/B_0 Proehl et al., JGR 2002

Parallel Mode Structure

Poloidal m L = 1/3



Global LFM-MHD Simulations of Magnetosphere

Solar wind measurements made by satellite at L1, or CME-solar wind coupled MHD codes  Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere

Goodrich et al. ‘98

L dependence of Ephi power

0.558-15 mHz Elkington, S. R., M. Wiltberger, A. A. Chan, and D. N. Baker,

J. Atmos. Solar Terr. Phys

., 66, 1371, 2004.

Azimuthal Distribution of P(Ephi)

Azimuthal Distribution of P(Ephi)

Azimuthal Mode Number from MHD Simulations and Ground Magnetometers Sept 98 storm MHD (Ephi) wave power in 0.14-15 mHz, low m modes Mathie & Mann, JGR, 2000

Frequency Dependence Bloom, R. M. and H. J. Singer,

JGR

, 100, 14943, 1995.

Convective Growth of Magnetopause K-H Waves

K-H Shear-Driven Instability

Direct Coupling of Solar Wind ULF Waves Kepko et al., GRL, 2002

3 MHz Solar Wind Pulsations

SW Density Driven Pulsations

 

Test Particle Simulations of Radiation Belts

2D: Drift motion of electrons and ions in the equatorial plane is followed using time varying electric and magnetic fields from global MHD simulation 3D: Bounce and drift motion of guiding center electrons in MHD fields; gyro, bounce and drift motion of Solar Energetic Particles (el, protons, Fe) Solar Energetic Particle (SEP) cutoffs calculated using MHD fields

MHD Fields Injection of RadBelt Electrons

Radiation Belt Electron Energization Processes Conserving First Invariant * Particles can be energized by: 1)Convection: steady, or substorm and storm-enhanced 2)Diffusion*: convection E fluctuations, ULF wave δE and δB  δE enhance diffusion 3) Drift time scale injection (Mar 91) a)Falthammar, JGR, 1965; b)Elkington et al., JGR, 2003

Diffusion Rates vs. L

Braughtigam & Albert, 2000, N=6, 10 Radial diffusion rates in model ULF wave fields D_LL ~ L N Falthammar, 1965 N=6, 10 Elkington et al., 2003 N=11 Selesnick et al., 97, 2000 N=12 Perry et al., JGR, 2005, N=6, 18 Perry includes δEφ, δBr, δB//, freq and L-dependent Power

MHD-Driven Phase Space Density AE8 Max-Initialized, Sept 98 Storm Fei et al., 2005

Drift Time Scale Injection from SSC’s Blake et al., 2005

E

F in equatorial plane from MHD simulation of March 24, 1991 CME-interplanetary shock compression of magnetopause.

E x B transport of ring of radiation belt electrons inward by inductive

E

F due to magnetopause compression dBz/dt.

MHD-Guiding Center Simulation Elkington et al., JASTP, 2002; 2004

Equatorial Plane Proton MHD Guiding Center Simulation March 24, 91 event Hudson et al., JGR, 1997

Average Count Rate of 10-20 MeV Electrons Mirroring at SAMPEX

Solar Proton Trapping Nov 01

New belt example: 24 Nov 2001

Mazur et al., SHINE mtg, 2004 Clear trapping of solar particles - no other source of heavy ions possible

Solar Energetic Particle Access

   Summary of ‘ULF Wave’ Effects on Energetic Particles Electrons interact diffusively with ULF waves with f ~ electron drift period while conserving first invariant Large amplitude distortion of magnetopause launches magnetosonic impulse outside range of linear ULF wave models, drift time scale injection of MeV electrons and protons (electrons unusual) Solar energetic particles trapped on drift time scale, stay trapped as long as 1 st invariant conserved (Young et al., 2002)

Higher Frequency Wave Mode Effects  Other, 1 st invariant violating processes responsible for energy/momentum diffusion and pitch angle diffusion at fixed L (VLF/ELF) Summers and Ma, JGR, 2000

m Externally and Internally Excited Pc5 (mHz) ULF Waves: low and high

Field Line Resonance

Dawn-Dusk Assymmetry in Toroidal Mode ULF Wave Power Duskside B-compression affects K-H instability threshold velocity shear (Lee et al., JGR, 1981) Sharper dawn-side radial gradient affects ionospheric screening (Glassmeir & Stellmacher, JGR, 2000)

Perry et al., JGR, 2005 Compressed (solid) vs. dipole (dashed) diffusion coefficients