Ion density and current distributions in a propagating current sheet, determined by microwave reflection technique

1969 ◽  
Vol 3 (2) ◽  
pp. 189-213 ◽  
Author(s):  
W. R. Ellis ◽  
R. G. Jahn
Keyword(s):  
Axial Current ◽  
Ion Current ◽  
Large Radius ◽  
Relative Importance ◽  
Current Pattern ◽  
Ion Density ◽  
Density Distributions ◽  
Hall Parameter ◽  
Electron Density And Temperature ◽  
Microwave Reflection

Electron and ion density distributions and the problem of electron/ion current partitioning are studied in a large radius Z-pinch in argon. Radial scans of the electron density and temperature proffles in the propagating sheet are obtained with a multi-purpose microwave interferometer which measures the complex refiexion coefficient from the plasma. At 70 GHz the probe resolves densities up to 1017 cm−3 over dimensions of ˜ 4 mm. Proffles of the electric and magnetic field components are obtained using standard probe techniques, and these data are used to calculate ion and electron current components in the sheet.Within the approximations of MHD theory, calculations show that the overall axial current pattern is built up of four interior zones alternately dominated by electron or ion current. This structure is observed to be closely correlated with variations of the Hall parameter, Wb/vc, about the value of unity through the sheet, which suggests that this parameter might be used as a guide to the relative importance of ion conduction in pinch discharge current sheets.

Numerical simulation of pulsed plasma sheath dynamics around a micro-sized tip

2013 ◽  
Vol 79 (5) ◽  
pp. 759-764
Author(s):  
H. GHOMI ◽  
A. MAHMOODPOOR ◽  
H. GOUDARZI ◽  
A. R. NIKNAM
Keyword(s):  
Cross Section ◽  
Temporal Evolution ◽  
Fluid Model ◽  
Rectangular Cross Section ◽  
Early Time ◽  
Plasma Sheath ◽  
Two Dimensional ◽  
Pulsed Plasma ◽  
Ion Density ◽  
Density Distributions

AbstractIn this paper the spatial and temporal evolution of pulsed plasma sheath around a micropatterned surface is investigated using two-dimensional fluid model. The simulation region is considered as a micro-sized tip with rectangular cross section. The effects of rise time on electric field, ion density distributions, and dose of ions impacting the target are studied. It is shown that the plasma sheath has a balloon-like behavior in the early time stages.

Ion Density Measurements in the Wake of a Hypersonic Sphere

1972 ◽  
Vol 50 (23) ◽  
pp. 2970-2990 ◽  
Author(s):  
L. Sévigny ◽  
D. Heckman ◽  
P. Caron
Keyword(s):  
Research Effort ◽  
Current Data ◽  
Distribution Data ◽  
Measured Temperature ◽  
Density Estimates ◽  
Ion Density ◽  
Density Distributions ◽  
Density Radius ◽  
Two Parameters ◽  
Mean Current

A report is presented of the results of a major research effort undertaken to determine experimentally, through the use of cylindrical electrostatic probes and existing probe theory, the levels of ion density in the turbulent wakes behind 2.7 in. diameter spheres flown at 14 500 ft/s in a ballistic range filled with nitrogen at 7.6 Torr and at 20 Torr. Measurements of the ion current distribution have been made by means of a transverse survey array of cylindrical electrostatic ion probes. Three static theories and three kinetic theories have been applied to the mean current data of the probes, and experimentally measured temperature and velocity distribution data for sphere wakes was used to construct radial distributions of ion density estimates for each theory. These radial distributions have been fitted with gaussian curves by the method of least mean squares. Two parameters of the ion density distributions are determined: the ion density on the axis of the wake and the ion density radius of the wake. These results have been compared with electron density levels in the wake deduced from microwave interferometer measurements and Langmuir probe instrumentation.

Global Ion Density Distributions Observed by Advanced Ionospheric Probe Onboard FORMOSAT-5 Satellite

2020 ◽  
Author(s):  
Chi-Kuang Chao
Keyword(s):  
Ionospheric Plasma ◽  
Spatial Scales ◽  
Plasma Concentrations ◽  
Quality Data ◽  
Ion Density ◽  
Great Opportunity ◽  
Density Distributions ◽  
Wide Range ◽  
Ionospheric Plasma Density

<p>A FORMOSAT-5 satellite has been launched on 25 August 2017 CST into a 98.28° inclination sun-synchronous circular orbit at 720 km altitude along the 1030/2230 local time sectors.  The orbital coverage provides a great opportunity to survey terrestrial ionosphere from equatorial to polar region every two days.  Advanced Ionospheric Probe (AIP) is a piggyback science payload developed by National Central University for the FORMOSAT-5 satellite to measure ionospheric plasma concentrations, velocities, and temperatures.  It is also capable of measuring ionospheric plasma density irregularities at a sample rate up to 8,192 Hz over a wide range of spatial scales.  In this poster, global ion density distributions observed by FORMOSAT-5/AIP in the pre-midnight sector can be averaged monthly and seasonally from in-situ measurement since November 2017.  Wave-3 and wave-4 patterns are clearly detected from the distributions and varied with season and solar cycle.  It is adversely indicated that FORMOSAT-5/AIP can provide high quality data to identify long-term ionospheric ion density variations.</p>

scholarly journals Theoretical simulation of O<sup>+</sup> and H<sup>+</sup> densities in the Indian low latitude F-region and comparison with observations

2002 ◽  
Vol 20 (12) ◽  
pp. 1959-1966 ◽  
Author(s):  
P. K. Bhuyan ◽  
P. K. Kakoty ◽  
S. B. Singh
Keyword(s):  
Solar Minimum ◽  
Low Latitude ◽  
Ion Density ◽  
Theoretical Simulation ◽  
Density Distributions ◽  
F Region ◽  
Modeling And Forecasting ◽  
Dependent Model ◽  
Time Dependent Model

Abstract. The O+ and H+ ion density distributions in the Indian low latitude F-region, within ± 15° magnetic latitudes, are simulated using a time dependent model developed on the basis of solution of the plasma continuity equation. The simulated ion densities for solar minimum June and December solstices are then compared with ionosonde observations from the period 1959–1979 and measurements made by the Indian SROSS C2 satellite during 1995–1996 at an altitude of ~ 500 km. The simulated O+ density has a minimum around pre-sunrise hours and a maximum during noontime. H+ density is higher at nighttime and lower during the day. The simulations reproduced the well-known equatorial ionization anomaly (EIA) observed in electron density at the peak of the F2-region in the Indian low latitude sector during solar minimum. In situ measurement of O+ density by the SROSS C2, however, showed a single peak of ionization around the equator.Key words. Ionosphere (equatorial ionosphere; modeling and forecasting)

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