scholarly journals Cluster EDI convection measurements across the high-latitude plasma sheet boundary at midnight

2001 ◽  
Vol 19 (10/12) ◽  
pp. 1669-1681 ◽  
Author(s):  
J. M. Quinn ◽  
G. Paschmann ◽  
R. B. Torbert ◽  
H. Vaith ◽  
C. E. McIlwain ◽  
...  
Keyword(s):  
Electric Fields ◽  
High Latitude ◽  
Plasma Sheet ◽  
Boundary Region ◽  
Electron Drift ◽  
Polar Cap ◽  
Static Structure ◽  
Boundary Crossings ◽  
Instruments And Techniques ◽  
Using Data

Abstract. We examine two crossings of three Cluster satellites from the polar cap into the high-latitude plasma sheet at midnight local time, using data from the Electron Drift Instrument (EDI). EDI measures the full electron drift velocity in the plane perpendicular to the magnetic field for any field and drift directions. The context of the measured convection velocities is established by their relation to the intense enhancements in 1 keV electrons, also measured by EDI, as the satellites move from the polar cap into the plasma sheet boundary. In both cases presented here, the cross B convection in the polar cap is anti-sunward (toward the nightside plasma sheet) with a small duskward component. As the satellites enter the plasma sheet boundary region, the dawn-dusk convective flow component reverses its sign, and the flow in the meridianal plane (toward the center of the plasma sheet) drops substantially. The relatively stable convection in the polar cap becomes highly variable as the PSBL is encountered. The timing and sequence of the boundary crossings by the Cluster satellites are consistent with a relatively static structure on a time scale of the few minutes in satellite separations. In one of the two events, the plasma sheet boundary has a spatially separate structure that is crossed by the satellites before entering the plasma sheet.Key words. Magnetospheric physics (electric fields; magnetopause, cusp and boundary layers; instruments and techniques)

scholarly journals A new southern high-latitude index

1998 ◽  
Vol 16 (12) ◽  
pp. 1589-1598 ◽  
Author(s):  
P. Ballatore ◽  
C. G. Maclennan ◽  
M. J. Engebretson ◽  
M. Candidi ◽  
J. Bitterly ◽  
...  
Keyword(s):  
High Latitude ◽  
Activity Level ◽  
Polar Cap ◽  
Geomagnetic Index ◽  
Level Indicator ◽  
Ae Index ◽  
Average Activity ◽  
Using Data ◽  
Auroral Phenomena ◽  
Southern High Latitude

Abstract. We have developed and examined a new regional geomagnetic index AES-80, defined similarly to the classical auroral electrojet AE index, using data from five Antarctic stations located at corrected geomagnetic latitudes about 80 °S. Because only sparse ground-based information can be derived from auroral latitudes in the Southern Hemisphere, and because no index comparable to AE can be constructed from locations in the south, the possibility of using AES-80 as a measure of high latitudes and polar cap activity is investigated. As a global average activity level indicator, it is found that in general AES-80 gives results rather similar to the classical AE index. However AES-80 provides a more robust measure of the occurrence of high-latitude geomagnetic activity.Key words. Magnetospheric physics (auroral phenomena; polar cap phenomena).

scholarly journals EDI convection measurements at 5-6 R<sub>E</sub> in the post-midnight region

1999 ◽  
Vol 17 (12) ◽  
pp. 1503-1512 ◽  
Author(s):  
J. M. Quinn ◽  
G. Paschmann ◽  
N. Sckopke ◽  
V. K. Jordanova ◽  
H. Vaith ◽  
...  
Keyword(s):  
Electric Fields ◽  
Temporal Variations ◽  
Equatorial Region ◽  
Frame Of Reference ◽  
Electron Drift ◽  
Ionospheric Model ◽  
Rotating Frame ◽  
Plasma Convection ◽  
High Data ◽  
Instruments And Techniques

Abstract. We present the first triangulation measurements of electric fields with the electron drift instrument (EDI) on Equator-S. We show results from five high-data-rate passes of the satellite through the near-midnight equatorial region, at geocentric distances of approximately 5–6 RE, during geomagnetically quiet conditions. In a co-rotating frame of reference, the measured electric fields have magnitudes of a few tenths of mV/m, with the E × B drift generally directed sunward but with large variations. Temporal variations of the electric field on time scales of several seconds to minutes are large compared to the average magnitude. Comparisons of the "DC" baseline of the EDI-measured electric fields with the mapped Weimer ionospheric model and the Rowland and Wygant CRRES measurements yield reasonable agreement.Key words. Magnetospheric physics (electric fields; plasma convection; instruments and techniques)

scholarly journals Using Data Assimilation to Reconstruct High‐Latitude Polar Cap Patches

Radio Science ◽  
2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Michael Negale ◽  
Jeffrey Holmes ◽  
Richard Parris ◽  
Daniel Ober ◽  
Eugene Dao ◽  
...  
Keyword(s):  
Data Assimilation ◽  
High Latitude ◽  
Polar Cap ◽  
Using Data

scholarly journals EDI electron time-of-flight measurements on Equator-S

1999 ◽  
Vol 17 (12) ◽  
pp. 1513-1520 ◽  
Author(s):  
G. Paschmann ◽  
N. Sckopke ◽  
H. Vaith ◽  
J. M. Quinn ◽  
O. H. Bauer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Amplitude Modulation ◽  
Electron Beams ◽  
Time Of Flight ◽  
Electron Drift ◽  
Plasma Convection ◽  
Instruments And Techniques ◽  
Flux Gate ◽  
Flight Measurements

Abstract. We present the first electron time-of-flight measurements obtained with the Electron Drift Instrument (EDI) on Equator-S. These measurements are made possible by amplitude-modulation and coding of the emitted electron beams and correlation with the signal from the returning electrons. The purpose of the time-of-flight measurements is twofold. First, they provide the drift velocity, and thus the electric field, when the distance the electrons drift in a gyro period becomes sufficiently large. Second, they provide the gyro time of the electrons emitted by the instrument, and thus the magnitude of the ambient magnetic field, allowing in-flight calibration of the flux-gate magnetometer with high precision. Results of both applications are discussed.Key words. Magnetospheric physics (electric fields; plasma convection; instruments and techniques)

High Field Electron Drift in a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Qing Gu ◽  
Eric A. Schiff ◽  
Jean Baptiste Chevrier ◽  
Bernard Equer
Keyword(s):  
Electric Fields ◽  
High Field ◽  
Drift Mobility ◽  
Time Range ◽  
Electron Drift ◽  
Parameter Change ◽  
Transient Photocurrent ◽  
Field Mobility ◽  
High Electric Fields ◽  
Electron Drift Mobility

We have measured the electron drift mobility in a-Si:H at high electric fields (E ≤ 3.6 x 105 V%cm). The a-Si:Hpin structure was prepared at Palaiseau, and incorporated a thickp+ layer to retard high field breakdown. The drift mobility was obtained from transient photocurrent measurements from 1 ns - 1 ms following a laser pulse. Mobility increases as large as a factor of 30 were observed; at 77 K the high field mobility de¬pended exponentially upon field (exp(E/Eu), where E u= 1.1 x 105 V%cm). The same field dependence was observed in the time range 10 ns – 1 μs, indicating that the dispersion parameter change with field was negligible. This latter result appears to exclude hopping in the exponential conduction bandtail as the fundamental transport mechanism in a-Si:H above 77 K; alternate models are briefly discussed.

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