scholarly journals Ion acoustic instability of HPT particles, FAC density, anomalous resistivity and parallel electric field in the auroral region

2003 ◽  
Vol 112 (4) ◽  
pp. 559-567
Author(s):  
C. S. Jayasree ◽  
G. Renuka ◽  
C. Venugopal
Keyword(s):  
Electric Field ◽  
Anomalous Resistivity ◽  
Auroral Region ◽  
Parallel Electric Field ◽  
Acoustic Instability ◽  
Ion Acoustic

A linear and quasi-linear investigation of the crossfield current-driven ion-acoustic instability

1982 ◽  
Vol 28 (2) ◽  
pp. 267-279 ◽  
Author(s):  
R. Bharuthram ◽  
M. A. Hellberg
Keyword(s):  
Linear Growth ◽  
Velocity Distribution Function ◽  
Linear Growth Rate ◽  
Particle Diffusion ◽  
Anomalous Resistivity ◽  
Heating Rates ◽  
Ion Heating ◽  
Acoustic Instability ◽  
Ion Acoustic ◽  
Drift Instability

The linear growth rate of the crossfield current-driven ion-acoustic instability is obtained for any equilibrium particle velocity distribution function of the type . Quasi-linear theory is then used to investigate the saturation of the instability. Several associated features, namely, particle diffusion in velocity space, anomalous resistivity, energy distribution and electron and ion heating rates are evaluated for a Maxwellian distribution. Finally, a brief comparison is made with the heating rates associated with the electron cyclotron drift instability.

scholarly journals Cluster observations and theoretical identification of broadband waves in the auroral region

2005 ◽  
Vol 23 (12) ◽  
pp. 3739-3752 ◽  
Author(s):  
M. Backrud-Ivgren ◽  
G. Stenberg ◽  
M. André ◽  
M. Morooka ◽  
Y. Hobara ◽  
...  
Keyword(s):  
Electric Field ◽  
Acoustic Waves ◽  
Auroral Region ◽  
Parallel Electric Field ◽  
Ion Acoustic Waves ◽  
Ion Cyclotron Waves ◽  
Linear Waves ◽  
Field Lines ◽  
Broadband Waves ◽  
The Waves

Abstract. Broadband waves are common on auroral field lines. We use two different methods to study the polarization of the waves at 10 to 180 Hz observed by the Cluster spacecraft at altitudes of about 4 Earth radii in the nightside auroral region. Observations of electric and magnetic wave fields, together with electron and ion data, are used as input to the methods. We find that much of the wave emissions are consistent with linear waves in homogeneous plasma. Observed waves with a large electric field perpendicular to the geomagnetic field are more common (electrostatic ion cyclotron waves), while ion acoustic waves with a large parallel electric field appear in smaller regions without suprathermal (tens of eV) plasma. The regions void of suprathermal plasma are interpreted as parallel potential drops of a few hundred volts.

Anomalous resistivity and the nonlinear evolution of the ion-acoustic instability

2006 ◽  
Vol 111 (A1) ◽  
Author(s):  
P. Petkaki ◽  
M. P. Freeman ◽  
T. Kirk ◽  
C. E. J. Watt ◽  
R. B. Horne
Keyword(s):  
Nonlinear Evolution ◽  
Anomalous Resistivity ◽  
Acoustic Instability ◽  
Ion Acoustic

Anomalous resistivity of a turbulent plasma in a strong electric field

1979 ◽  
Vol 21 (3) ◽  
pp. 475-500 ◽  
Author(s):  
Y. Kiwamoto ◽  
H. Kuwahaara ◽  
H. Tanaca
Keyword(s):  
Electric Field ◽  
Collision Frequency ◽  
Strong Electric Field ◽  
Turbulent Plasma ◽  
Electron Drift ◽  
Anomalous Resistivity ◽  
Effective Collision Frequency ◽  
Ion Acoustic ◽  
Average Electron ◽  
Effective Collision

The enhanced effective collision frequency in a turbulent plasma produced by a strong electric field is studied using a small toroidal device. The collision frequency is presented as a function of the electric field E and the average electron drift velocity. Two collision frequency regimes are identified. In the regime I where v ∝ E½, the current driven ion-acoustic turbulence is considered responsible.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

scholarly journals Brief Communication: The double layer in the separatrix region during magnetic reconnection

2015 ◽  
Vol 22 (2) ◽  
pp. 167-171
Author(s):  
J. Guo ◽  
B. Yu
Keyword(s):  
Electron Beam ◽  
Magnetic Reconnection ◽  
Double Layer ◽  
Particle In Cell ◽  
Acoustic Instability ◽  
Ion Acoustic ◽  
Evolution Stage ◽  
Spatial Size ◽  
Electron Holes ◽  
Observation Results

Abstract. With two-dimensional (2-D) particle-in-cell (PIC) simulations we investigate the evolution of the double layer (DL) driven by magnetic reconnection. Our results show that an electron beam can be generated in the separatrix region as magnetic reconnection proceeds. This electron beam could trigger the ion-acoustic instability; as a result, a DL accompanied with electron holes (EHs) can be found during the nonlinear evolution stage of this instability. The spatial size of the DL is about 10 Debye lengths. This DL propagates along the magnetic field at a velocity of about the ion-acoustic speed, which is consistent with the observation results.

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