Simulation of Van Allen Probes plasmapause encounters

Abstract

We use an E × B‐driven plasmapause test particle (PTP) simulation to provide global contextual information for in situ measurements by the Van Allen Probes (Radiation Belt Storm Probes (RBSP)) during 15–20 January 2013. During 120 h of simulation time beginning on 15 January, geomagnetic activity produced three plumes. The third and largest simulated plume formed during enhanced convection on 17 January, and survived as a rotating, wrapped, residual plume for tens of hours. To validate the simulation, we compare its output with RBSP data. Virtual RBSP satellites recorded 28 virtual plasmapause encounters during 15–19 January. For 26 of 28 (92%) virtual crossings, there were corresponding actual RBSP encounters with plasmapause density gradients. The mean difference in encounter time between model and data is 36 min. The mean model‐data difference in radial location is 0.40 ± 0.05 RE. The model‐data agreement is better for strong convection than for quiet or weakly disturbed conditions. On 18 January, both RBSP spacecraft crossed a tenuous, detached plasma feature at approximately the same time and nightside location as a wrapped residual plume, predicted by the model to have formed 32 h earlier on 17 January. The agreement between simulation and data indicates that the model‐provided global information is adequate to correctly interpret the RBSP density observations.

Temperature Dependence of Plasmaspheric Ion Composition

“…An example of this adjustment is depicted in Figure 3 and described below, using previously published Van Allen Probes A data from 15 January 2013 (Goldstein et al, 2014;Genestreti et al, 2017). An example of this adjustment is depicted in Figure 3 and described below, using previously published Van Allen Probes A data from 15 January 2013 (Goldstein et al, 2014;Genestreti et al, 2017).…”

“…The Van Allen Probes data used herein are from previously published work (Genestreti et al, 2017;Goldstein et al, 2014). The Van Allen Probes data used herein are from previously published work (Genestreti et al, 2017;Goldstein et al, 2014).…”

Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations

“…Wave power distribution: Although EMIC waves were observed at many different locations, we use the wave properties measured by GOES 13, because when mapped to the magnetic equator, it was the closest to the balloon. The waves observed by the magnetometer of GOES 13 lasted from ∼02:52:00-03:12:00 UT, lagging behind the REP event by a little less than 4 min, likely because GOES 13 entered the rotating plasmapause at a later time than balloon 1G ( [Goldstein et al, 2014], cf. Figure 2 in the present paper), and the high density plasmasphere has been suggested to be a preferable region for EMIC wave occurrence [Horne and Thorne, 1993;Spasojević et al, 2004;Yahnin and Yahnina, 2007;Chen et al, 2010;Usanova et al, 2013].…”

“…Since GOES 13 does not provide plasma density observations, we calculate the plasma density using the upper hybrid resonance (UHR) frequency provided by the Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) [Kletzing et al, 2013] on the Van Allen Probes. At 03 UT, balloon 1G was shown by a plasmapause test particle (PTP) model [Goldstein et al, 2014] to be at the main plasmapause wrapped inside a residual plume (Figure 2). At the same time, as suggested by both EMFISIS UHR frequency observations (Figure 1f ) and the PTP model [Goldstein et al, 2014], the Van Allen Probes were outside the plasmasphere, where the plasma density could be very different from the wave region.…”

“…At 03 UT, balloon 1G was shown by a plasmapause test particle (PTP) model [Goldstein et al, 2014] to be at the main plasmapause wrapped inside a residual plume (Figure 2). At the same time, as suggested by both EMFISIS UHR frequency observations (Figure 1f ) and the PTP model [Goldstein et al, 2014], the Van Allen Probes were outside the plasmasphere, where the plasma density could be very different from the wave region. However, as the plasmapause rotated eastward [Goldstein et al, 2014], when the spacecraft came back to their apogees (with an L value similar to the REP event) at 12 UT, the spacecraft was inside the plasmasphere, as indicated by the EMFISIS UHR frequency observations (Figure 1f ).…”