Electrons and positive ions in an auroral arc

Abstract

Two new types of British sounding rocket, a Skylark 12 and a Fulmar, were launched from Andøya in northern Norway, on 21 November 1976, in an experiment to study the particle streams and plasma waves associated with an auroral arc. We report here the first results obtained from channel multipliers and electrostatic analysers carried on the Skylark 12 (designation SL 1422) to detect electrons in the range 0.5–25 keV,and positive ions of 0.5–25 keV per unit charge. We believe that the results are unique and constitute the first detailed comparison of positively- and negatively-charged particles in the region of an auroral arc. They have been made possible by the combined advantages of high altitude (715 km), which enables ions to be studied before absorption in the atmosphere, long range (780 km), which allows a complete traversal of an auroral structure, and new analysers, which extend the dynamic range of measurement.