North Star Plasma-Jet Space Experiment

Abstract

The objective of the Active Plasma Experiment North Star mission was to study the interaction of artificially produced aluminum ion plasma jets with the space environment. Two separate plasma jets were injected almost perpendicular to the local magnetic field during the North Star experiment. The jets were created using an explosivetype generator designed to produce a high-speed (7-42-km/s) aluminum ion plasma jet with plasma densities exceeding 10 9 cm −3 at a distance 170 m from the plasma-jet source. The first plasma-jet injection occurred at an altitude of 360 km and was preceded by the release of an artificial air cloud. The second injection occurred at an altitude of 280 km and did not include the air cloud. Interactions of the plasma jet with the local space environment and artificial air cloud were monitored using instrumentation on three diagnostic payloads, ground-based optical sensors, and space-based optical sensors. An overview is provided of the experiment, along with a summary of the principal results from the mission.

Whistler Waves' Propagation in Plasmas With Systems of Small‐Scale Density Irregularities: Numerical Simulations and Theory

“…The impact of a system of multiple density irregularities on the process of VLF wave propagation in a magnetized plasma should be taken into account when planning active and laboratory plasma experiments or interpreting their measurements. Note that such irregularities can occur naturally in the auroral ionosphere, as well as during active experiments with the clouds of easily ionized substances (Kelley & Livingston, ) and artificial plasma jets (Erlandson et al, ).…”

“…As a result of the interferences between the modes of the various field‐aligned irregularities, a “collective” waveguide mode can be formed with its own dispersion law and specific properties. Besides active HF heating experiments, similar problems may arise for natural small‐scale irregularities, which can occur in the strongly disturbed auroral ionosphere, and for ionospheric disturbances generated in active experiments with artificial plasma clouds (Erlandson et al, ; Kelley & Livingston, ) in presence of VLF waves.…”

Rocket‐Released Neutral Clouds in the Ionosphere: Formation, Evolution, and Detection

“…The release enhanced auroral particle precipitation; Holmgren et al (1980) mentions prior barium releases that also increased particle precipitation. The North Star experiment (Erlandson et al, 2004) released two high speed aluminum jets, one into an artificial air cloud and another into the natural environment. The air cloud affected the ionization and resulted in a flow of high speed neutrals as well.…”