Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared
Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared
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太阳风几乎消失当天环、磁层顶和尾流的地面扰动
DOI：
10.1029/2000ja000251
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
J. Scudder
中科院分区：
文献类型：
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作者：
V. Jordanova;C. Farrugia;J. Fennell;J. Scudder
我们研究了太阳风密度异常低（约0.1 cm−3）的一天的环电流动力学。地磁活动的内部磁层测量显示地磁非常安静。1999年5月11日的值为|Dst| < 10nt, Kp = 0+。地球静止轨道上的磁场非常接近偶极。我们模拟了这一时期环电流离子种群的全球演变，并比较了磁层顶、环、磁尾和场向电流对Dst指数的影响。利用5月9日极地卫星磁层离子组成光谱仪（MICS）和HYDRA仪器测量的H+、He+和O+能量和俯仰角分布作为动力学模型的初始条件。将模型结果与5月11日的极地数据进行比较，我们发现了显著的一致性，证明了我们的模型对这些磁层条件的适用性。我们将模拟的H+和He+离子分布与统计研究推断的安静时环电流分布进行了比较，我们发现，作为一个总体趋势，模拟结果比统计模式的值要低。由环和磁层顶电流引起的地磁场扰动在5月11日准单调减小，分别达到~ 5和~ 3 nT的极限量级。这些值大大小于从统计研究中获得的~ 20nt安静时间值。
We study ring current dynamics on a day of exceptionally low solar wind density (of ∼0.1 cm−3). Inner magnetospheric measurements of geomagnetic activity show geomagnetic quiet par excellence. On May 11, 1999, the values were |Dst| < 10 nT and Kp = 0+. The field at geostationary orbit was very close to dipolar. We simulate the global evolution of the ring current ion population during this period and compare the effect of the magnetopause, ring, magnetotail, and field‐aligned currents on the Dst index. Measured H+, He+, and O+ energy and pitch angle distributions by the Magnetospheric Ion Composition Spectrometer (MICS) and HYDRA instruments on Polar on May 9 are used as initial conditions for our kinetic model. Comparing model results with Polar data on May 11, we find remarkable agreement, proving the applicability of our model for these magnetospheric conditions. We compare modeled H+ and He+ ion distributions with quiet time ring current distributions inferred from statistical studies, and we find that as a general trend, the simulation results have lower values than the statistical patterns. The ground magnetic field disturbances due to the ring and the magnetopause currents decrease quasi‐monotonically on May 11, reaching limiting magnitudes of ∼5 and ∼3 nT, respectively. These values are substantially smaller than the ∼20 nT quiet time values obtained from statistical studies.
1998年5月4日的大规模地磁效应
DOI：
--
发表时间：
2003
期刊：
Advance in Space Research 31(4)
影响因子：
--
作者：
Farrugia;C.J.;K.Yumoto;et al.
通讯作者：
et al.