Mirror instability and the origin of morningside auroral structure

Abstract

The Laboratory Operations of The Aerospace Corporation is conducting experimental an(l theoretical investigations necessary for the evaluation and application of seientific advances to new military space systems.Versatility and flexibility have been developed to a high degree by the laboratory personnel in dealing with the many problems encountered in the nation's rapidly developing space sysu~ms. Expertise in the latest: scientific developments is vita] to the accomplishment of tasks related to these problems. The laboratories that contribute to this research are:Aerophysics Laboratory: Launch vehicle and reentry aerodynamic.s and heat transfer, Jrropulsion chemistry and fluid mechanics, structural mechanics, flight dynamics; high-temperature thermornechanlcs, gas kinetics and radiation; research in environmental chemistry and contamination; cw and pulsed chemical laser development including chemical kinetics, spectroscopy, optical resonators and beam pointtng, atmospheric propagation, laser effects and countermeaSLlres. Chemistry and Physics Laboratory:Atmospheric chemical reactions, atmospheric optics~ light scattering, state-specific chemical reactions and radiation transport 1n rocket plumes, applied laser spectroscopy, laser chemistry, battery el(:!ctrochemistry, space vacuum and radiation effects on materials, lubrication and surface phenomena, thermionic emission, photosensitive materials and detectors, atomic frequency standards, and bioenvironmental n~search and monitoring. Electronics Research Laboratory:Microelectronics, GaAs IOy7-noise and power devices, semiconductor lasers, electromagnetic and optical propagation phenomena, quantum electronics, laser communications, lidar, and electro-optics; communicatj on sciences, applied electronics, semiconductor crystal and device physics, radiometric imaging; millimeter-'wave and microwave technology.Information Scij~nces Research Office: Program verification, program translatio~·-p€~rformance·-sensitive system -'design, distributed architectures for spaceborne computers, fault-tolerant computer systems, artificial intelligence, and microelectronics applications.Mate:dals Sciences Laboratory: Development of new materials: metal matrix composites,-polymers~ new forms of carbon; component failure analysis and reliability; fracturl~ mechanics and stress corrosion; evaluation of materials in space environment; materials performance in space transportation systems; analysis of sy':tems vulnerability and survivability in enemy-induced envi:conments. Space Sciences Laboratory:Atmospheric and ionospheric physics, radiation from the atmosphere, dens~and composition of the upper atmosphe"re, aurorae and airg10\7; magnetospheric physics, cosmic rays, generation and propagation of plasma waves tn the magnetosphere; solar physics, infrared astronomy; the effects of nuclear explosions, magnetic storms, and solar activity on the earth's atmosphere, ionosphere, and magnetosphere; the effects of optical, electromagnetic, and particulate radiations in space on space systems....

Relative drift between black aurora and the ionospheric plasma

“…They also remarked that the general eastward drift of the observed black patches is consistent with the gradient-B curvature drift of trapped energetic electrons in the magnetosphere, and suggested that the black patches might represent structures in the high-energy electron population, without specifying what these "structures" could be. This model is based on the work by Chiu et al (1983), who argued that the precipitating hot electrons that create optical signatures are gradient drifting azimuthally on trajectories which can depart significantly from the ionospheric convection path. Results from combined FAST and airborne auroral imager studies by Peticolas et al (2002) indicate (their Fig.…”

THEMIS observations of electron cyclotron harmonic emissions, ULF waves, and pulsating auroras

“…The idea is not theoretically new. Chiu et al [1983] proposed that the spatial modulation of the equatorial magnetic field and ambient plasma by a mirrormode wave, which is also the suggested mechanism of our observed ULF waves [see also Takahashi et al, 1990], can modulate the growth rate of the electron cyclotron waves, either electromagnetic or electrostatic, and in turn modulate the precipitation rate of auroral electrons. Also, AshourAbdalla and Kennel [1978] found that the local growth rate and spatial amplification of the ECH instability are crucially controlled by the "cold" electron plasma and/or its ratios to the "hot" population in density and temperature.…”

The Magnetosphere

“…46). Chiu et al (1983) have argued that the velocity shear associated with the underlying magnetospheric convec tion pattern should tend to align any spatial maxima in auroral-electron precipitation with equipotentials of the convection eletric field. 38.…”

“…Ion velocity distributions(Chiu et al, 1983), represented via contours of constant and equally spaced logio/, that would theoretically result from mappings (consistent with Liouville*s theorem) from source locations to (L, Φ) = (7, ± 7Γ/2). Sources: (a) a Maxwellian of temperature 1 keV at L = 13; and (b) a field-aligned beam of directed energy 0.5 keV and temperature 0.5 keV at L = 10 (sin φ < 0).…”