Dynamic features of plasmapause revealed by in situ measurements from Van Allen and
THEMIS Probes
Sam Califf et al.
Density from Spacecraft Potential
• RBSP– N = 7241*exp(-Vsc/0.356) + 114.6*exp(-Vsc/2.073)– Calibrated with upper hybrid (EMFISIS), June 3-5, 2013, RBSPA fit applied to RBSPB– Scott Thaller
• THEMIS– THEMIS A (different parameters for each probe)
• N = (10^(-Vsc/25.5)*18000 + 10^(-Vsc/5)*6e4 + 10^(-Vsc/2)*5e6 + 10^(-Vsc/0.4)*1e11)/Vthermal
– Brian Walsh, Toshi Nishimura
• Plasmapause: minimum radial distance with density below 50 cm-3
Plasmapause Observations
• Minimum Lpp = 2.7 near midnight at ~50 hr
Plasmapause Observations
• Minimum Lpp = 2.7 near midnight at ~50 hr
• Duskside bulge
Plasmapause Observations
• Minimum Lpp = 2.7 near midnight at ~50 hr
• Correlation with Dst
Plasmapause inferred from MagEIS measurements
• 38 keV injection stops at L = 2.75• Lpp from spacecraft potential = 2.7
Inward diffusion
Injection stops L = 2.75 L=3
L=3.75L=3.5L=3.25
L=2.5
MagEIS Data
Event: June 27 – July 3, 2013
• Use RBSP and THEMIS to observe evolution of the plasmasphere
RBSP
THEMIS
min Dst ~ 50 hr
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