First Author: Jordanova, V. K.,

Co-Authors: C. J. Farrugia, R. B. Torbert, J. F. Fennell, M.F. Thomsen, G. D. Reeves, and D. J. McComas,

Title: Modeling the ring current response to the July 14, 2000, solar storm,

Reference: AGU Fall Meeting, San Francisco, CA, Dec. 15-19, 2000.

Reference Type: Contributed Talk

CEPPAD: false

CAMMICE: true

RAPID: false

Abstract: 
A flare observed by SOHO/LASCO on July 14, 2000, lead to very extreme interplanetary parameters at 1 AU about 1 day later and associated intense geomagnetic activity. Thus, preliminary $Dst$=-300 nT and $Kp$=9 were recorded. These were caused by a coronal mass ejection (CME) driving a very strong shock which reached Earth about 5 hours ahead of the CME. The sheath region was characterized by $B_z$ fluctuations of peak-to-peak amplitude about 30 nT, and the CME contained a negative to positive $B_z$ variation. The negative phase lasted for $\sim$6 hours and $B_z$ reached a minimum of about -55 nT. To simulate ring current energization during this disturbed period, we use our kinetic drift-loss model with initial and boundary conditions provided by energetic particle data from the HYDRA and MICS instruments on the POLAR spacecraft (orbiting near the postnoon-premidnight meridian) and plasma data from the LANL MPA and SOPA instruments at geosynchronous orbit. We study the effect of a) the extremely large $B_z$ fluctuations in the CME sheath, and b) the intense negative $B_z$ in the CME. Both of these interplanetary sources caused considerable geomagnetic activity ($Kp$=8 to 9) despite their disparity as interplanetary triggers.