Waterhole: An Auroral-Ionosphere Perturbation Experiment
- S.-I. Akasofu and
- J.R. Kan
Published Online: 26 MAR 2013
Copyright 1981 by the American Geophysical Union.
Physics of Auroral Arc Formation
How to Cite
Whalen, B. A., Yau, A. W., Creutzberg, F. and Pongratz, M. B. (1981) Waterhole: An Auroral-Ionosphere Perturbation Experiment, in Physics of Auroral Arc Formation (eds S.-I. Akasofu and J.R. Kan), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM025p0199
- Published Online: 26 MAR 2013
- Published Print: 1 JAN 1981
Print ISBN: 9780875900506
Online ISBN: 9781118664360
- Auroras—Addresses, essays, lectures
A sounding rocket carrying 100 kg of high explosives and plasma diagnostic instrumentation was launched from Churchill Research Range on 6 April 1980 over a premidnight auroral arc. The object of the experiment was to produce an ionospheric hole or plasma density depletion at about 300 km altitude on field lines connected to an auroral arc. The plasma depletion is produced when the explosive by-products (mostly water) charge-exchange with the ambient O+ ions and then rapidly recombine. It was speculated that the presence of the “hole” would interfere with the field-aligned current systems associated with the arc and would in turn perturb the auroral source mechanism. The release occurred about 10 km poleward of the auroral arc fieldlines. As expected, a large ionospheric hole was detected by rocket-borne plasma sensors. Within a few seconds following the release (a) the energetic electron precipitation observed in the hole dropped to background levels, (b) the luminosity of the auroral arc observed by a ground-based auroral scanning photometer decreased by a factor of two, and (c) the ionospheric E region density below the hole decayed at a rate consistent with a sudden reduction in particle precipitation. The simultaneous onset of these gross changes in electron precipitation coincident with the release strongly suggests a cause and effect relationship. In particular, these results suggest that the ionospheric plasma and the field-aligned current systems play a crucial role in the auroral acceleration process.