MSSL Space Plasma Science Nuggets
Structure and variability of the auroral acceleration region
Publication date: 5 February 2013
Bright auroral arc appear when charged particles from the magnetosphere are accelerated into the upper atmosphere. Collisions between charged particles and neutrals excite the electrons in the neutral particles which then de-excite by emitting auroral light. Particles, in particular electrons, are accelerated out of the magnetosphere and into the atmosphere by magnetic-field-aligned electric potential drops in a region known as the auroral acceleration region (AAR). In a recent paper, Forsyth et al.  investigated the temporal variability and spatial structure in one such region.
What is the source of magnetotail flux-ropes?
Publication date: 12 December 2011
Travelling compression regions (TCRs) are perturbations in the magnetotail lobe magnetic field caused by structures moving Earthward or tailward within the plasma sheet. Previous works have suggested that these structures are created by either time-dependant reconnection occurring at a single X-line, forming a flux-bulge-type structure, or space-variant reconnection at multiple X-lines, forming flux-rope-type structures. By analysing a TCR and its source structure using the Cluster spacecraft, Beyene et al. (2011) have endeavoured to determine which of these mechanisms creates TCRs.
Particle Distributions in the Magnetotail
Publication date: 17 August 2011
Calculating currents from four spacecraft
Publication date: 1 May 2011
Ampere's law tells us that the curl of a magnetic field is proportional to current density. In order to measure the curl of a magnetic field in space, one needs to know approximate the variation of the magnetic field between four non-coplanar points. Such measurements are achieved by the Cluster quartet.
Discovery of the 'Travelling Magnetopause Erosion Region'
Publication date: 6 February 2009