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Title: Direct comparison of 1-m irregularity phase velocities and ion acoustic speeds in the auroral E region ionosphere

Abstract

Simultaneous coherent and incoherent scatter measurements from a common ionospheric volume are used to investigate the relationship between the phase velocity V{sub ph} of meter wavelength irregularities generated by the two-stream instability and the ambient ion acoustic speed C{sub s} in the auroral electrojet plasma, with the purpose of testing the widely accepted conviction that V{sub ph} is always limited at C{sub s}. Since it is not clear if the charged particles behave isothermally or adiabatically, the authors used several options for C{sub s} suggested in the literature, including (1) isothermal behavior for both ions and electrons, (2) isothermal ions and adiabatic electrons with 3 degrees of freedom, and (3) adiabatic electrons with 3 degrees of freedom and adiabatic ions with 1 degree of freedom. The comparison shows that option 3, in which {gamma}{sub e} = 5/3 and {gamma}{sub i} = 3, is rather unlikely. On the other hand, they find that option 2 ({gamma}{sub e} = 5/3, {gamma}{sub i} = 1) is more appropriate for use in the ion acoustic speed for meter wavelength waves. The analysis shows that on the average, phase velocities are limited to values which are {approximately} 15% higher than C{sub s} in line withmore » the nonlinear kinetic model of the modified two-stream instability developed recently by Robinson and Honary (1990). Finally, in spite of the great deal of uncertainty involved in the V{sub ph} estimates, there is convincing evidence in the data showing that at times another mechanism, other than anomalous electron gas heating, is involved which allows for V{sub ph} to receive values well above C{sub s}.« less

Authors:
 [1];  [2]
  1. Univ. of Crete, Iraklion (Greece)
  2. Max-Planck-Inst. fuer Aeronomie, Katlenburg-Lindau (West Germany)
Publication Date:
OSTI Identifier:
5102998
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research; (United States)
Additional Journal Information:
Journal Volume: 95:A11; Journal ID: ISSN 0148-0227
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AURORAL ZONES; RADIOWAVE RADIATION; E REGION; PHASE VELOCITY; BACKSCATTERING; COMPARATIVE EVALUATIONS; ELECTROJETS; ELECTRON DRIFT; ELECTRON TEMPERATURE; HEATING; ION DRIFT; MHZ RANGE; RADAR; TWO-STREAM INSTABILITY; CURRENTS; EARTH ATMOSPHERE; ELECTRIC CURRENTS; ELECTROMAGNETIC RADIATION; EVALUATION; FREQUENCY RANGE; INSTABILITY; IONOSPHERE; MEASURING INSTRUMENTS; PLANETARY IONOSPHERES; PLASMA INSTABILITY; PLASMA MICROINSTABILITIES; RADIATIONS; RANGE FINDERS; SCATTERING; VELOCITY; 640201* - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena

Citation Formats

Haldoupis, C, and Schlegel, K. Direct comparison of 1-m irregularity phase velocities and ion acoustic speeds in the auroral E region ionosphere. United States: N. p., 1990. Web. doi:10.1029/JA095iA11p18989.
Haldoupis, C, & Schlegel, K. Direct comparison of 1-m irregularity phase velocities and ion acoustic speeds in the auroral E region ionosphere. United States. https://doi.org/10.1029/JA095iA11p18989
Haldoupis, C, and Schlegel, K. Thu . "Direct comparison of 1-m irregularity phase velocities and ion acoustic speeds in the auroral E region ionosphere". United States. https://doi.org/10.1029/JA095iA11p18989.
@article{osti_5102998,
title = {Direct comparison of 1-m irregularity phase velocities and ion acoustic speeds in the auroral E region ionosphere},
author = {Haldoupis, C and Schlegel, K},
abstractNote = {Simultaneous coherent and incoherent scatter measurements from a common ionospheric volume are used to investigate the relationship between the phase velocity V{sub ph} of meter wavelength irregularities generated by the two-stream instability and the ambient ion acoustic speed C{sub s} in the auroral electrojet plasma, with the purpose of testing the widely accepted conviction that V{sub ph} is always limited at C{sub s}. Since it is not clear if the charged particles behave isothermally or adiabatically, the authors used several options for C{sub s} suggested in the literature, including (1) isothermal behavior for both ions and electrons, (2) isothermal ions and adiabatic electrons with 3 degrees of freedom, and (3) adiabatic electrons with 3 degrees of freedom and adiabatic ions with 1 degree of freedom. The comparison shows that option 3, in which {gamma}{sub e} = 5/3 and {gamma}{sub i} = 3, is rather unlikely. On the other hand, they find that option 2 ({gamma}{sub e} = 5/3, {gamma}{sub i} = 1) is more appropriate for use in the ion acoustic speed for meter wavelength waves. The analysis shows that on the average, phase velocities are limited to values which are {approximately} 15% higher than C{sub s} in line with the nonlinear kinetic model of the modified two-stream instability developed recently by Robinson and Honary (1990). Finally, in spite of the great deal of uncertainty involved in the V{sub ph} estimates, there is convincing evidence in the data showing that at times another mechanism, other than anomalous electron gas heating, is involved which allows for V{sub ph} to receive values well above C{sub s}.},
doi = {10.1029/JA095iA11p18989},
url = {https://www.osti.gov/biblio/5102998}, journal = {Journal of Geophysical Research; (United States)},
issn = {0148-0227},
number = ,
volume = 95:A11,
place = {United States},
year = {1990},
month = {11}
}