Artificial Aurora Experiments and Application to Natural Aurora
- 1SPACE VEHICLES DIRECTORATE, Air Force Research Laboratory, United States
A review is given of the effects observed during injections of powerful electron beams from sounding
rockets into the upper atmosphere. Data come from in situ particle and wave measurements near a beam
emitting rocket and ground-based optical, wideband radiowave, and radar observations. The overall data
cannot be explained solely by collisional degradation of energetic electrons but require collisionless beam
plasma interactions (BPI) be taken into account. The beam-plasma discharge theory describes the features
of the region near a beam-emitting rocket, where the beam-excited plasma waves energize plasma electrons,
which then ignite the discharge. The observations far beneath the rocket reveal a double-peak structure of
artificial auroral rays, which can be understood in terms of the beam-excited strong Langmuir turbulence
being affected by collisions of ionospheric electrons. This leads to the enhanced energization of ionospheric
electrons in a narrow layer termed the plasma turbulence layer (PTL), which explains the upper peak. Similar
double-peak structures or a sharp upper boundary in rayed auroral arcs have been observed in the auroral
ionosphere by optical, radar, and rocket observations, and called Enhanced Aurora. A striking resemblance
between Enhanced and Artificial Aurora altitude profiles indicates that they are created by the above BPI
process which results in the PTL.
Keywords: active experiments, Artificial Aurora, electron beam-plasma instability, Langmuir turbulence, Enhanced Aurora, active experiments in the iomosphere, Artificial aurora, Beam-plasma discharge, Enhanced Aurora
Received: 20 Dec 2018;
Accepted: 28 Feb 2019.
Edited by:Ioannis A. Daglis, National and Kapodistrian University of Athens, Greece
Reviewed by:Alla V. Suvorova, National Central University, Taiwan
Konstantinos Papadopoulos, University of Maryland, College Park, United States
Copyright: © 2019 Mishin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Evgeny V. Mishin, Air Force Research Laboratory, SPACE VEHICLES DIRECTORATE, Dayton, United States, email@example.com