Rocket measurement of the secondary electron spectrum in an aurora

Feldman, P. D.; Doering, J. P.; Moore, Jason H.

doi:10.1029/ja076i007p01738

Cited by 27 publications

(9 citation statements)

References 15 publications

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“…Theoretical [Rees et al, 1969;Banks et al, 1974] and experimental [Opal et al, 1971] descriptions of the secondary electron production processes have been developed and used to predict auroral emission intensities [Rees and Jones, 1972;Sharp and Rees, 1972]. Feldman et al [1971] reported a measurement of the differential electron flux above 7 V. They found that the structure predicted by theory was not present in the data.…”

mentioning

confidence: 99%

Low-energy auroral electrons

Sharp¹,

Hays²

1974

J. Geophys. Res

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A measurement of the low‐energy auroral electron flux distribution between 0.5 and 80 eV reveals structure between 0.5 and 10.0 eV. The structure is due to the thermal electron Maxwellian distribution and electron energy loss to thermal electrons, molecular nitrogen, and atomic oxygen. Some physical process in the auroral plasma causes the deduced loss function to differ from theory. Reasonable agreement is obtained between calculated and measured N2 second positive emission.

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confidence: 99%

Low-energy auroral electrons

Sharp¹,

Hays²

1974

J. Geophys. Res

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“…An additional concern is that the existence of the EA and ECS mode requires comparable fractions of hot and cold populations. While secondary auroral electrons do provide a warm population of electrons, their densities are typically on the order of a few percent [Rees, 1969;Feldman et al, 1971;Gérard, 1972], though this has only a minor impact on the mode dispersion. Auroral electron energies (∼1-10 s of keV) meet cyclotron resonance conditions for n = 1 and n = 2, but only lower energy electrons (100 s of eV) satisfy Landau resonance with these modes.…”

Section: Discussionmentioning

confidence: 99%

Theoretical constraints on the generation mechanism of auroral medium frequency burst radio emissions

et al. 2011

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[1] Auroral medium frequency (MF) burst is an impulsive auroral radio emission observed at ground level between ∼1.3 and 4.5 MHz for a few minutes at substorm onsets. Despite multiple suggested theories, the exact generation mechanism for MF burst remains unknown. The foremost theory suggests that MF burst originates from Langmuir or upper hybrid waves excited over a range of altitudes in the bottomside or topside F region, which linearly mode convert to the electromagnetic LO mode, gaining access to ground level. Analysis of plasmas with two electron components implies the existence of additional normal modes, commonly referred to as the electron acoustic (EA) and electron cyclotron sound (ECS) modes, which have been suggested to potentially play a role in the generation of MF burst. Analytical calculations using Waves in Homogeneous, Anisotropic Multicomponent Plasmas, or WHAMP, and other dispersion-solving calculations are applied to applicable ionospheric normal modes (RX, LO, Langmuir or upper hybrid, EA, and ECS), compared to previous results, and applied to MF burst and the auroral plasma environment. Computation of resonant parallel energies suggests that, in the presence of an auroral electron distribution, instability of EA, ECS, LX, and Langmuir or upper hybrid modes is possible. The same analysis suggests that LO and RX modes are unlikely to be directly excited. Excitation of the EA or ECS mode in the frequency range applicable to MF burst is found to be more favorable for higher ionospheric plasma densities ( f pe /f ce > 2.36) and higher secondary electron temperatures (T h ≈ 100s of eV). Growth rate calculations suggest that growth of the EA or ECS mode is excitable by the auroral electron beam with higher growth rates for the ECS mode.

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“…The differential flux of primary and secondary electrons under auroral activity has been the subject of a series of experimental measurements [Feldman et al, 1972;Arnoldy and Choy, 1973;Reasoner and Chappell, 1973;Feldman and Doering, 1975;Matthews et al, 1976]. A common feature of all these rocket experiments is that between 30 and 85 eV, where the measurements overlap in energy, the electron flux data can be fitted by a power law E -• with 0.5 < a < 1.0.…”

Section: Introductionmentioning

confidence: 99%

Collisionless Effects on the Spectrum of Secondary Auroral Electrons at Low Altitudes.

Papadopoulos

Rowland

1977

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Rocket measurement of the secondary electron spectrum in an aurora

Cited by 27 publications

References 15 publications

Low-energy auroral electrons

Low-energy auroral electrons

Theoretical constraints on the generation mechanism of auroral medium frequency burst radio emissions

Collisionless Effects on the Spectrum of Secondary Auroral Electrons at Low Altitudes.

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