A predictive model of geosynchronous magnetopause crossings

NCUIR > College of Earth Sciences > Graduate Institute of Space Science > journal & Dissertation > Item 987654321/50421

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Title:	A predictive model of geosynchronous magnetopause crossings
Authors:	Dmitriev,A;Suvorova,A;Chao,JK
Contributors:	太空科學研究所
Keywords:	INTERPLANETARY MAGNETIC-FIELD;STEADY-STATE RESPONSE;LOW-LATITUDE STATIONS;ART. NO. 1341;SOLAR-WIND;GEOMAGNETIC STORMS;RING CURRENT;DAYSIDE MAGNETOPAUSE;SUDDEN IMPULSES;ORBIT
Date:	2011
Issue Date:	2012-03-27 17:31:28 (UTC+8)
Publisher:	國立中央大學
Abstract:	We have developed a model predicting whether or not the magnetopause crosses geosynchronous orbit at a given location for given solar wind pressure P(sw), B(z) component of the interplanetary magnetic field (IMF), and geomagnetic conditions characterized by 1 min SYM-H index. The model is based on more than 300 geosynchronous magnetopause crossings (GMCs) and about 6000 min when geosynchronous satellites of GOES and Los Alamos National Laboratory (LANL) series are located in the magnetosheath (so-called MSh intervals) in 1994-2001. Minimizing of the P(sw) required for GMCs and MSh intervals at various locations, B(z), and SYM-H allows describing both an effect of magnetopause dawn-dusk asymmetry and saturation of B(z) influence for very large southward IMF. The asymmetry is strong for large negative B(z) and almost disappears when B(z) is positive. We found that the larger the amplitude of negative SYM-H, the lower the solar wind pressure required for GMCs. We attribute this effect to a depletion of the dayside magnetic field by a storm time intensification of the cross-tail current. It is also found that the magnitude of threshold for B(z) saturation increases with SYM-H index such that for small negative and positive SYM-H the effect of saturation diminishes. This supports an idea that enhanced thermal pressure of the magnetospheric plasma and ring current particles during magnetic storms results in the saturation of magnetic effect of the IMF B(z) at the dayside magnetopause. A noticeable advantage of the model's prediction capabilities in comparison with other magnetopause models makes the model useful for space weather predictions.
Relation:	JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Appears in Collections:	[Graduate Institute of Space Science] journal & Dissertation

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