Low altitude particle acceleration region deduced from time-dependent observations of auroral structures.

Particle Acceleration and Wave Phenomena in the Auroral Region

1 I n t r o d u c t i o n The auroral region of the terrestrial magnetosphere is a fascinating part of space, and also a part that can be investigated in some detail with satellites, sounding rockets and groundbased instruments. The second EGS Alfv~n conference held in Stockholm May 3-7 1999 was devoted to auroral particle acceleration and related topics. This meeting produced a variety of inte...

Satellite Observations of Auroral Acceleration Processes

Measurements with satellite and sounding rocket borne instruments contain important information on remote and local processes in regions containing matter in the plasma state. The characteristic features of the particle distributions can be used to explain the morphology and dynamics of the different plasma populations. Charged particles are lost from a region due to precipitation into the atmo...

Auroral ion outflow: low altitude energization

The SIERRA nightside auroral sounding rocket made observations of the origins of ion upflow, at topside F-region altitudes (below 700 km), comparatively large topside plasma densities (above 20 000/cc), and low energies (10 eV). Upflowing ions with bulk velocities up to 2 km/s are seen in conjunction with the poleward edge of a nightside substorm arc. The upflow is limited within the poleward e...

AKR breakup and auroral particle acceleration at substorm onset

[1] The dynamical behavior of auroral kilometric radiation (AKR) is investigated in connection with auroral particle acceleration at substorm onsets using high-time-resolution wave spectrograms provided by Polar/PWI electric field observations. AKR develops explosively at altitudes above a preexisting low-altitude AKR source at substorm onsets. This ‘‘AKR breakup’’ suggests an abrupt formation ...

Particle Acceleration by Alfvén Waves in the Auroral Zone