A region of intense plasma wave turbulence on auroral field lines

Plasma wave measurements from the Hawkeye 1 and Imp 6 satellites show that a broad region of intense plasma wave turbulence occurs on the high-latitude auroral field lines at altitudes ranging from a few thousand kilometers in the ionosphere to many earth radii in the distant magnetosphere. This turbulence occurs in an essentially continuous band on the auroral L shells at all local times around the earth and is most intense during periods of auroral activity. The electric field intensity of this turbulence is often quite large, with maximum field strengths of about 10 mV m−1 and peak intensities in the frequency range 10–50 Hz. Magnetic field perturbations indicative of field-aligned currents and weak bursts of whistler mode magnetic noise are also observed in the same region as the electric field turbulence. In the local afternoon and evening the electric field turbulence is closely associated with V-shaped auroral hiss emissions. In some cases the electric field turbulence appears as a lowering and intensification of the low-frequency portion of the auroral hiss spectrum. Comparisons with plasma measurements and with similar measurements from other satellites strongly suggest that this plasma wave turbulence occurs on magnetic field lines which connect with regions of intense inverted V electron precipitation at low altitudes and with regions of intense earthward plasma flow in the distant magnetotail. The plasma instabilities which could produce this turbulence and the possible role which this turbulence may play in the heating and acceleration of the auroral particles are considered.