Event Title

Electrostatic Double Layers

Location

Yosemite National Park

Start Date

2-8-1974 8:45 AM

End Date

2-8-1974 9:15 AM

Description

An efficient mechanism for acceleration of auroral particles may be through electrostatic double layers. Birkeland-currents can create favorable conditions for double layers by reduction of the electron density at high altitudes. When double layers appear, a reduction of the current density will occur due to broadening of the current-carrying region in response to the increased resistivity associated with the double layers. However, the double layers will persist, and a balance can be established between the current-broadening and concentrating effects operative in the low ionosphere. Methods to observe double layers with rockets and satellites include measurements of pitch-angle distributions with high resolution, three-axis electric double probes, and topside sounders. Due to the small field-aligned extent (10-100 Debye-lengths) of double layers, they will only show up as spikes of short duration in the output signal of a double probe. Such signals should therefore not be discarded as spurious, but analyzed carefully. Simultaneous measurements of Birkeland-currents, electron density, ion composition, and fluxes and energies of precipitating and upgoing particles are also very desirable, but they cannot alone discriminate between double layers and other anomalous resistivity effects.

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Feb 8th, 8:45 AM Feb 8th, 9:15 AM

Electrostatic Double Layers

Yosemite National Park

An efficient mechanism for acceleration of auroral particles may be through electrostatic double layers. Birkeland-currents can create favorable conditions for double layers by reduction of the electron density at high altitudes. When double layers appear, a reduction of the current density will occur due to broadening of the current-carrying region in response to the increased resistivity associated with the double layers. However, the double layers will persist, and a balance can be established between the current-broadening and concentrating effects operative in the low ionosphere. Methods to observe double layers with rockets and satellites include measurements of pitch-angle distributions with high resolution, three-axis electric double probes, and topside sounders. Due to the small field-aligned extent (10-100 Debye-lengths) of double layers, they will only show up as spikes of short duration in the output signal of a double probe. Such signals should therefore not be discarded as spurious, but analyzed carefully. Simultaneous measurements of Birkeland-currents, electron density, ion composition, and fluxes and energies of precipitating and upgoing particles are also very desirable, but they cannot alone discriminate between double layers and other anomalous resistivity effects.