Active Experiments in Space: The Future

Abstract

Planned active space experiments and ideas for future active space experiments are reviewed. Three active experiments being readied are DSX (Demonstration and Space eXperiments), SMART (Space Measurement of Rocket-released Turbulence), and BeamPIE (Beam Plasma Interaction Experiment). Ideas for future experiments include relativistic-electron-beam experiments for magnetic-field-line tracing, relativistic-electron-beam experiments to probe the middle atmosphere, plasma-wave launching using superparamagnetic-nanoparticle amplification of magnetic fields, the heavy-ion mass loading of collisionless magnetic-field-line reconnection, the use of electrostatically charged tethers to pitch-angle scatter radiation-belt particles, cold plasma releases to modify magnetospheric plasma physics, and neutral-gas releases to enhance neutral-particle imaging of the magnetosphere. Technologies that are being developed to enable future space active experiments are reviewed: this includes the development of compact relativistic accelerators, superparamagnetic particle amplified antennae, CubeSats, and a new understanding of how to control dynamic spacecraft charging. New capabilities to use laboratory facilities to design space active experiments as well as new computer-simulation capabilities to design and understand space active experiments are reviewed.

Active Precipitation of Radiation Belt Electrons Using Rocket Exhaust Driven Amplification (REDA) of Man‐Made Whistlers

“…In addition, ambient power‐line harmonics (Fedorov et al., 2021 ; Park & Helliwell, 1978 ), intentional VLF transmissions from terrestrial power lines and high‐power VLF transmitters can leak into space where they may interact with energetic electrons in the Earth's magnetosphere (Hua et al., 2020 ; Ma et al., 2017 ; Ross et al., 2019 ). Several man‐made facilities have been developed to study this wave‐particle‐interaction process including VLF transmitters (Helliwell, 1977 , 1988 ), high‐power HF facilities for modulations of natural ionosphere currents in the ionosphere (Guo et al., 2021 ), large satellite antennas driven by high power signal generators, electron beams that are modulated at VLF rates, and high‐speed neutral injections that rapidly photoionize in sunlight (Borovsky & Delzanno, 2019 ; Sotnikov et al., 2018 ). These techniques require dedicated, expensive engineering efforts for design, construction, and testing before they are deployed on the ground or in space.…”

Stable transport of relativistic electron beams in plasmas

“…Collimated relativistic electron beams (REBs) with high energy are widely used in astrophysics, inertial confinement fusion (Craxton et al 2015;Yang et al 2016), plasma based accelerators (Geddes et al 2004;Esarey, Schroeder & Leemans 2009) and new diagnostic technologies (Barbieri et al 2000). In these areas, many potential application scenarios such as space active experiments (Marshall et al 2014;Borovsky & Delzanno 2019;Xue et al 2020) in the middle atmosphere require long-distance transport of electron beams. Moreover, the plasmas produced by the gas ionization and the plasmas of the middle atmosphere have clear effects on REB transport, such as self-modulation (Pukhov et al 2011;Schroeder et al 2011).…”

Strong Amplification of ELF/VLF Signals in Space Using Neutral Gas Injections From a Satellite Rocket Engine

“…Whistler modes that propagate in the ionosphere and magnetosphere have been excited by ground based transmitters such as SIPLE Antarctica (Helliwell, 1977), the world's high power VLF navigation transmitters (Ma et al., 2017; Meredith et al., 2019; Parrot et al., 2007; Ross et al., 2019; Záhlava et al., 2018; S. Zhao, Zhou, et al., 2019), and the high power HF facilities in Arecibo, Puerto Rico (Pradipta et al., 2007) and HAARP, Alaska (Cohen & Golkowski, 2013; Golkowski et al., 2019), or modulation of energetic electron beams on the Space Shuttle (Carlsten et al., 2019). Three current experimental efforts (Borovsky & Delzanno, 2019) for space‐based VLF wave generation are supported in the United States by (1) the Air Force Research Laboratory with the DSX large dipole antenna operational from June 2019 to transmit VLF waves in space (Scherbarth et al., 2009), (2) the Los Alamos National Laboratory with a VLF precipitation experiment scheduled for April 2021 to launch the Beam Plasma Interactions Experiment (Beam‐PIE) with electron beam generation on a sounding Rocket (Carlsten et al., 2019), and (3) the Naval Research Laboratory with an injection of 1.5 kg of barium to form hypersonic ions that are converted into lower‐hybrid, whistler or magnetosonic waves (Ganguli et al., 2015, 2019). Alternate techniques for whistler mode generation are being studied because these waves are difficult to radiate with conventional antennas where the free space wavelengths (10–1,000 km) are so much longer than a practically realizable vertical monopole antenna, and the radiation efficiency is exceedingly small.…”