Artificial particle and wave stimulation in the trigger experiment

Abstract

The Trigger experiment was designed to test the response of the auroral ionosphere to an impulsive release of a hot, dense plasma. It consisted of a sounding rocket payload divided into two parts, an instrumented diagnostic section and a cesium doped high explosive canister. When the two sections were separated by about 1 km, but close to the same magnetic field line, the cesium high explosive was ignited and the plasma around the payload was observed to increase briefly by a factor of 4 in density and a factor of 2 in temperature. A variety of particle and field phenomena occurred in rapid succession after the cesium release. A drastic increase in the field aligned charged particle flux was observed over the approximate energy range 10 eV to more than 300 keV, starting about 150 ms after the release and lasting about 1 second. There is also evidence of a second particle burst, starting one second after the release and lasting for tens of seconds. A transient electric field pulse of 200 mV/m appeared just before the particle flux increase began. Additional effects include electrostatic waves associated with the cesium cloud boundary. The field aligned currents associated with the electric field pulse and cloud conductivity gradient may be responsible for the observed electron acceleration in a manner similar to the electrodynamic origin of auroral arcs.