Influence of the solar wind dynamic pressure on the decay and injection of the ring current
Influence of the solar wind dynamic pressure on the decay and injection of the ring current
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DOI：
10.1029/2003ja009851
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发表时间：
2003-09
影响因子：
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通讯作者：
Chuanbing Wang;Chuanbing Wang;J. Chao;C.‐H. Lin
中科院分区：
文献类型：
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作者：
Chuanbing Wang;Chuanbing Wang;J. Chao;C.‐H. Lin
根据1964年1月至2001年7月期间的太阳风资料和OMNI数据库地磁指数Dst，研究了太阳风动压对地磁流衰减和注入的影响。发现当环电流的位置越靠近地球，太阳风动压越大，环电流的衰减时间越短。对于向北的行星际磁场（IMF），衰减时间t = 8.70 exp（6.66/（6.04 + P）），P为太阳风动压，单位为纳帕。通过使每小时Dst的计算值与实测值之差的均方根误差最小化，还发现环电流注入率与太阳风动压成正比，在向南的IMF期间，其幂指数等于0.2。这意味着当磁层被高太阳风动压压缩时，环电流注入增加。在此基础上，我们证明了当考虑太阳风动压对环电流衰减和注入的影响时，奥布莱恩和McPherron [2000 a]模型对Dst的预测是有改进的，特别是对强磁暴。
The influence of the solar wind dynamic pressure on the decay and injection of thering current is investigated empirically, on the basis of the solar wind and the geomagneticindex Dst of the OMNI database, for the period from January 1964 to July 2001. Wefound that when the position of the ring current is closer to the Earth for a higher solarwind dynamic pressure, the decay time of the ring current decreases. The decay time, inhours, varies as follows, t = 8.70 exp(6.66/(6.04 + P)), for northward interplanetarymagnetic fields (IMF), where P is the solar wind dynamic pressure in nanopascals. It isalso found, by minimizing the root mean square errors of the hourly Dst differencebetween the calculated values and the measured ones, that the ring current injection rate isproportional to the solar wind dynamic pressure, with a power index equal to 0.2 duringsouthward IMF. This implies that the ring current injection increases when themagnetosphere is more compressed by high solar wind dynamic pressure. On the basis ofour new results we demonstrate that the predictions of Dst using O’Brien andMcPherron’s [2000a] model are improved, especially for intense geomagnetic stormswhen the influence of the solar wind dynamic pressure on the decay and injection of ringcurrent is taken into consideration.