Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection

Details Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection

Oct 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003p%26ss...51..797s&link_type=abstract

Planetary and Space Science, Volume 51, Issue 12, p. 797-812.

Computer Science

1

Dayside Aurora, Particle Precipitation, Plasma Convection, Solar Wind-Magnetosphere Interaction

Scientific paper

In this report we describe two different aspects of the dynamical behaviour of the cusp aurora which we refer to as (1) spontaneous and (2) directly driven events, respectively. The first aspect consists of a series of auroral activations/expansions observed during steady interplanetary magnetic field (IMF) and solar wind plasma conditions. This aspect we attribute to reconnection transients at the dayside magnetopause (flux transfer events). Applying a combination of ground and satellite observations, we document the auroral, particle precipitation, plasma convection, and field-aligned current signatures of these events. Emphasis is placed on the spatio-temporal evolution of the auroral and plasma convection events (pulsed ionospheric flows; PIFs) in the cusp ionosphere. Thus, we are able to document the multi-phase association between auroral brightenings/poleward moving auroral forms (PMAFs) and PIFs. Characteristic cusp ion steps (energy versus latitude profile) are observed during north-south traversals of the cusp by spacecraft Polar and DMSP F13 at the time of PMAFs. From the ground-satellite conjunction studies we infer the stepped cusp to be due to the traversal through a sequence of poleward-propagating open flux tubes originating in a pulsed magnetopause reconnection process. The region of the cusp ion steps is shown to be permeated by fine structure in the electron precipitation comprising a broad energy spectrum (30-600eV). This observation accounts for the long auroral rays, spanning much of the altitude range 120-500km, which are so typical for the cusp region. The second aspect of cusp dynamics consists of rapid transitions in the auroral configuration which are directly driven by abrupt changes in the external conditions, mainly northward and southward rotations of the IMF vector. Focus is placed on the rapidity of the transitions in the IMF-magnetosphere interconnection topology. The presence of a bifurcated (hybrid) cusp, with 1-5keV auroral arcs excited at its poleward boundary, is documented during the northward IMF (clock angle range 45-70°) phase of one transition.

Affiliated with

Also associated with

No associations

Rating

Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection 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 Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spontaneous and driven cusp dynamics: Optical aurora, particle precipitation, and plasma convection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1034879