漂移壳追踪方法与内辐射带的长期变化  

DRIFT SHELL TRACING METHOD AND THE SECULAR VARIATION OF INNER RADIATION FLUXES

作　　者：方晓华[1] 濮祖荫[1] 

机构地区：[1]北京大学地球物理系,100871

出　　处：《空间科学学报》2000年第2期150-158,共9页Chinese Journal of Space Science

基　　金：国家自然科学基金!49684003;高等学校博士学科点专项科研基金

摘　　要：地磁场的长期变化如何改变辐射带结构，如何在当前年代下恰当地使用AE－8／AP－8模型，目前国内外对此问题存在着很大的争议．我们在物理分析的基础上给出了当前年代下使用辐射带模型AP－8的漂移壳追踪方法DSTM（DriftShellThacingMethod）．计算结果表明地磁场的长期变化对内辐射带的通量分布有着显著的影响．30－40年来，南大西洋通量异常区中心位置向西和向北发生偏移，高粒子辐射区域的范围扩大．在辐射带内边缘，由于漂移壳偏移，造成辐射强度显著改变，同一空间点的通量值最多可相差到3－4个数量级．The AE-8/AP-8 models, which were constructed by NASA with satellite obser-vation data in the 1960s and 1970s, have long been considered to be the standardtrapped radiation models. It seems that they will continuously be used for a certainperiod of time in the future. The weakening of the geomagnetic field causes the driftshell of a charged particle to descend and the structure of the Trapped RadiationBelt to deform. Thus it is of importance to correctly use the AE-8/AP-8 models inthe contemporary era. However, up to now there seems to be no consensus on thisissue- On the basis of physical analysis, we propose the Drift Shell Tracing Method(DSTM) in this paper to solve the problem. The DSTM provides a reasonable wayto apply the standard trapped radiation models within the adiabatic approximation. The calculation results indicate that the change of the geomagnetic field playsa significant role in the particle redistribution in the inner zone. It is found that inthe past three decades,the central location of the particle South Atlantic Anomaly(SAA) has drifted westward almost 20° in longitude and northward almost 1Oo inlatitude. In the altitudes of 300-400 kilometers, the intensity of proton flaxes hasvaried dramatically and the flux difference at the same location can even be up to3-4 orders of magnit1lde.

关 键 词：漂移壳 南大西洋异常区 内辐射带长期变化 DSTM 

分 类 号：P353[天文地球—空间物理学]