A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling

Details A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling

Jun 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998jgr...10311787k&link_type=abstract

Journal of Geophysical Research, Volume 103, Issue A6, p. 11787-11796

Physics

23

Magnetospheric Physics: Mhd Waves And Instabilities

Scientific paper

We present a globally integrated substorm (GIS) model in which the patchy-bursty tail reconnection process at ~20-35RE and the magnetosphere-ionosphere (M-I) coupling process form a global feedback system to cause substorms. We identify the necessary and sufficient conditions for the expansion onset in the near-Earth plasma sheet. The necessary condition for substorm onset is an abrupt convection braking in the near-Earth plasma sheet at a rate >=~3(mV/m)/RE, which is equivalent to dipolarizing the tail-like field at a rate >=~0.5 nT/s. The sufficient condition requires the disrupted tail current to be carried away by the Alfvén wave to form the substorm current wedge. These conditions must be satisfied by any onset mechanism. The Alfvén wave launched by the dipolarization-induced electric field must carry away the disrupted tail current from the dipolarization region. As an example, we show that substorm expansion onset can be triggered by abruptly braking a bursty bulk flow of ~3 mV/m within ~1RE. The disrupted tail current at the expansion onset is ~105A/RE carried away by the Alfvén wave launched by the dipolarization-induced electric field of ~14 mV/m. Substorm expansion onset in the ionosphere occurs ~1 min later when the Alfvén wave is reflected at the ionosphere. The dipolarization-induced tail reconnection and the M-I coupling form a feedback system to power the ongoing expansion phase which typically lasts ~30 min. As the dipolarizing region expands tailward, the expansion phase turns into recovery phase when the local tail current becomes too weak to sustain the expansion phase and the aurora activities start to retreat equatorward.

Affiliated with

Also associated with

No associations

Rating

A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A globally integrated substorm model: Tail reconnection and magnetosphere-ionosphere coupling will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1333558