Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 1.490
IF1.490
IF 5-year value: 1.445
IF 5-year
1.445
CiteScore value: 2.9
CiteScore
2.9
SNIP value: 0.789
SNIP0.789
IPP value: 1.48
IPP1.48
SJR value: 0.74
SJR0.74
Scimago H <br class='widget-line-break'>index value: 88
Scimago H
index
88
h5-index value: 21
h5-index21
Volume 26, issue 6
Ann. Geophys., 26, 1507–1516, 2008
https://doi.org/10.5194/angeo-26-1507-2008
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 26, 1507–1516, 2008
https://doi.org/10.5194/angeo-26-1507-2008
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.

  11 Jun 2008

11 Jun 2008

Simulation of field-aligned H+ and He+ dynamics during late-stage plasmasphere refilling

J. Krall1, J. D. Huba1, and J. A. Fedder2 J. Krall et al.
  • 1Plasma Physics Div., Naval Research Lab., Code 6790, 4555 Overlook Ave., SW, Washington, D.C., 20375-5346, USA
  • 2Icarus Research, Inc., P.O. Box 30780, Bethesda, MD 20824-0780, USA

Abstract. The refilling of the plasmasphere for 3≤L≤4 following a model storm is simulated over long times (days) using the NRL ionosphere code SAMI2 (Sami2 is Another Model of the Ionosphere). Refilling is dependent on the supply of topside H+ and He+ ions with the result that H+ refilling rates decrease and He+ refilling rates generally increase with increasing F10.7 index. Both early- and late-stage refilling are affected by net ion flows from the warmer to the colder geomagnetic hemisphere. When these flows are strong, the ability of the "winter helium bulge" to increase He+ refilling rates is suppressed. When neutral winds are not included, refilling rates fall, typically by a factor of two. In most cases, late-stage He+ refilling is proportional to H+ refilling, with typical He+/H+ density ratios of 2% for solar minimum and 10% for solar maximum. For high values of F10.7, He+ refilling exhibits a strong diurnal variation so that the He+/H+ density ratio varies by as much as a factor of two during late-stage refilling. Finally if the plasmasphere is left undisturbed, the H+ density can refill for as long as five weeks at L=3 and ten weeks at L=4, with saturation densities nearly an order of magnitude greater than typical observed densities. This confirms that the plasmasphere at these L values rarely obtains saturation.

Publications Copernicus
Download
Citation