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Magnetic field‐aligned potential drops due to electrostatic ion cyclotron turbulence
Author(s) -
Hudson M. K.,
Lysak R. L.,
Mozer F. S.
Publication year - 1978
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl005i002p00143
Subject(s) - electric field , gyroradius , physics , cyclotron , magnetic field , atomic physics , field line , electric potential , turbulence , computational physics , harmonics , voltage , quantum mechanics , thermodynamics
Measurements of DC and AC electric fields and plasma densities on the S3‐3 satellite have shown that electrostatic ion cyclotron (EIC) turbulence is associated with significant DC electric fields parallel to auroral field lines. The EIC mode has been identified in regions of strong DC electric fields and magnetic field aligned currents by AC electric field and density fluctuations with frequency components between the local hydrogen gyrofrequency and its harmonics, and by wave vector polarization primarily perpendicular to the magnetic field at wavelengths of an ion gyroradius. The anomalous resistivity has been computed for measured AC electric fields of 50 mV/m in the EIC mode, yielding ∼1 mV/m DC parallel electric fields for measured currents of ∼10 µA/m². This theoretical result implies that several kV potential drops will occur if the anomalous resistivity region extends over several thousand kilometers along auroral field lines. This is adequate to accelerate auroral particles to observed energies and consistent with the scale height over which parallel electric fields and EIC turbulence are statistically observed on S3‐3.