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