| ABSTRACT
Storms and substorms
are both driven by earthward convection enhanced by magnetic reconnection in the
plasma sheet. Substorm is driven by the M/DTXL (mid-to-distant-tail-X-line) beyond
~30 Re radial distance during the growth phase and by the NEXL (near-Earth-X-line)
within ~30 Re during the expansion phase. Cowling current intensifies by the
blockage of the northward Hall current due to lack of the
radial currents or azimuthal pressure gradient in the midnight sector of
the near-Earth
plasma sheet. Interaction of intensified Cowling current loop with the
near-Earth plasma sheet causes dipolarization.
Dipolarization-induced thinning, tailward of the dipolarizing region,
can cause the NEXL formation to
drive the substorm expansion phase. Further intensifications of the
Cowling current in the substorm
current wedge, the tailward expansion of dipolarization region and the
expansion of the auroral bulge
are all driven by the NEXL during the expansion phase.
A ring current injection conjecture is proposed to order the storm
intensity based on the X-line location.
Ring current intensifies by convection driven by the NEXL during
the substorm expansion phase to
produce intense storms. On the other hand, ring current intensifies
by the MDXL in the absence of the
substorms to produce small storms. Results obtained previously
with the Rice Convection Model
coupled to an equilibrium magnetic-field solver indicate that
the entropy function PV5/3 must be
non-adiabatically reduced if plasma-sheet flux tubes are to
be injected into the heart of the storm-time ring
current. Magnetic reconnection in the plasma sheet reduces
PV5/3, and the effect is stronger if the X-line is
closer to the Earth. It is estimated that an X-line must form
within ~25 RE of Earth in order for the
reconnected flux tubes to penetrate deep into the heart of the
ring current to produce major storms.
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