Jordanova, V. K.,
Co-Authors: R. M. Thorne, C. J. Farrugia, Y. Dotan, J. F. Fennell, M. F. Thomsen, G. D. Reeves, and D. J. McComas,
Title: Ring Current Dynamics During the 13-18 July 2000 Storm Period,
Reference: Solar Physics, 204, 361-375, 2001.
Reference Type: Published Journal
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CAMMICE: true
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Abstract:
We study the development of the terrestrial ring current during the time interval of July 13-18, 2000, which consisted of two small to moderate geomagnetic storms followed by a great storm with indices Dst=-300 nT and Kp=9. This period of intense geomagnetic activity was caused by three coronal mass ejecta (CME) driving three interplanetary shocks, the last shock being very strong reached Earth at about 14 UT on July 15. We note that (a) the sheath region behind the third shock was characterized by Bz uctuations of *35 nT peak-to-peak amplitude, and (b) the CME contained a negative to positive Bz variation extending for about 1 day, with a *6 hours long negative phase and a minimum Bz of about -55 nT. Both of these interplanetary sources caused considerable geomagnetic activity (Kp=8 to 9) despite their disparity asinterplanetary triggers. We used our global ring current- atmosphere interaction model with initial and boundary conditions inferred from measurements f! rom the hot plasma instruments on the Polar spacecraft and the geosynchronous LANL satellites, and simulated the time evolution of H + , O + , and He + ring current ion distributions. We found that the O + content of the ring current increased after each shock and reached maximum values of ~60% near minimum Dst of the great storm. We calculated the growth rate of EMIC waves and found that the wave gain of O + band waves is greater and is located at larger L shells than that of the He + band waves. Isotropic pitch angle distributions indicating strong plasma wave scattering were observed by the IPS sensor on Polar at the locations of maximum predicted wave gain, in good agreement with model simulations.
