Substorm currents: Growth phase and onset

摘要: Magnetic field models are used to study electric currents that flow during growth phases and onsets of magnetospheric substorms. Large cross-tail between altitudes about 7 10 RE required near midnight phase in order produce the observed magnetic perturbations at synchronous altitude. Considerations particle fluxes needed carry showed current can be carried by drift a population whose energy density is 20 keV/cm³. This frequently present altitude after injection events. However, model calculations require establishment large beyond phase. No observations substantial flux increases within region interest could found. As partial explanation this problem, we found modest increase current. The increased unaccelerated preexisting particles changing play significant role altering process involves positive feedback effect, with carrying more as soon any perturbation begins stretch tail lines. It concluded extensive changes pitch angle distributions equatorial 8 RE. Such also will help determine whether plasma injected substorms primarily introduced slowly build up or suddenly local conversion onset. In first case, an event would represent inward motion which already exists substorm latter strong impulsive acceleration intrinsic part process. For our calculations, onset modeled diverting ionosphere wedge midnight. lines collapse dramatically even if only portion diverted. At same time, satellite outside sees become taillike. suggested diversion electron enough initiate substorm. Ion reduced substantially dipolar ion remains large. Finally, it noted very shell splitting effects should seen diverted