Rocket measurements of plasma densities and temperatures in visual aurora

1969 ◽  
Vol 47 (18) ◽  
pp. 1913-1927 ◽  
Author(s):  
A. G. McNamara
Keyword(s):  
Electron Density ◽  
Langmuir Probe ◽  
Optical Emission ◽  
Emission Region ◽  
Electron Component ◽  
Direct Measurements ◽  
Background Density ◽  
Vertical Thickness ◽  
Accuracy Of Measurement ◽  
Rocket Measurements

Direct measurements in active visual auroral forms using electrostatic plasma probes are described. On-board probes and an ejected Langmuir probe were used to provide maximum accuracy of measurement and freedom from perturbations. An electron density of 9.5 × 105 electrons/cm3 was found within a visual band, with a background density of 1.5 × 105 electrons/cm3 outside the band. The ionization maximum occurred at 107 km altitude, with a half-density vertical thickness of 7 km. The temperature of the thermal electrons over the interval 100 km to 168 km was found to range from 500 °K to 1400 °K. A hyperthermal electron component was also observed. A rocket-borne photometer determined the height of the optical emission region, and an array of optical, radio, and magnetic ground-based instruments were used to provide supporting geophysical data, and to define the position and variations of the auroral forms.

The Effects of Modulation on an RF Discharge in Silane and on the Deposited a-Si:H

1987 ◽  
Vol 98 ◽  
Author(s):  
L. J. Overzet ◽  
J. T. Verdeyen ◽  
R. M. Roth ◽  
F. F. Carasco
Keyword(s):  
Electron Density ◽  
Average Power ◽  
Optical Emission ◽  
Rf Discharge ◽  
Absorption Coefficients ◽  
Average Value ◽  
Optical Bandgaps ◽  
Time Average ◽  
Substrate Temperatures ◽  
Attachment Process

ABSTRACTThe time evolution of the electron density and the optical emission intensity in response to a square wave modulated RF excitation of helium-silane mixtures has been studied and compared to that for the more conventional CW discharge. In addition, the films deposited from CW and modulated RF glows have-been compared on the basis of absorption coefficients and photoconductivities. Films deposited from modulated glows at substrate temperatures below 200°C have significantly smaller optical bandgaps than those deposited from comparable CW discharges. The bulk electron density in the modulated discharge undergoes a complex temporal variation and its time average value can be significantly larger than that in the CW glow despite the lower average power. A dissociative attachment process involving silane radicals, SiHn (n = 1 to 3), is identified as the most probable cause.

Plasmaspheric response to the geomagnetic storm period March 20–23, 1990, observed by the ACTIVNY (MAGION-2) satellite

1992 ◽  
Vol 70 (7) ◽  
pp. 569-574 ◽  
Author(s):  
M. Förster ◽  
N. Jakowski ◽  
A. Best ◽  
J. Smilauer
Keyword(s):  
Magnetic Storm ◽  
Electron Density ◽  
Geomagnetic Storm ◽  
Joule Heating ◽  
Growth Phase ◽  
Langmuir Probe ◽  
Atomic Oxygen ◽  
Scale Height ◽  
Ionospheric Response ◽  
Increased Pressure

Langmuir probe data obtained during the storm period March 20–23, 1990, on board the MAGION-2 subsatellite of the ACTIVNY experiment are analyzed to study the plasmaspheric and ionospheric response to a magnetic storm. The data indicate a well-pronounced equatorward edge of the electron density trough in the afternoon (18:15 LT) at about 800 km height that moves towards lower latitudes during the course of the storm. It is interesting to note that the electron density inside the plasmasphere is increased by more than 20% in the morning shortly after sunrise (07:30 LT). This is due to enhanced O+ densities in the lower plasmasphere during the growth phase of the geomagnetic storm as measured by the ion mass spectrometer NAM-5 onboard the main satellite. It is suggested that the source for the increased density is thermospheric Joule heating at auroral latitudes with a commensurate increase in thermospheric pressure. This increased pressure causes the local thermosphere to expand both upward and equatorward. The increased atomic-oxygen scale height coupled with equatorward motion of fhermospheric perturbations results in an increased O density and resulting O+ density within the lower plasmasphere. The observations indicate a storm-induced compression of the plasmasphere that favourizes an enhanced outflow of plasma into the ionosphere leading to an increased nighttime F2-layer ionization and a depletion of the plasmasphere during the following hours.

scholarly journals Machine Learning Prediction of Electron Density and Temperature from Optical Emission Spectroscopy in Nitrogen Plasma

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1221
Author(s):  
Jun-Hyoung Park ◽  
Ji-Ho Cho ◽  
Jung-Sik Yoon ◽  
Jung-Ho Song
Keyword(s):  
Machine Learning ◽  
Electron Temperature ◽  
Real Time ◽  
Electron Density ◽  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Plasma Nitridation

We present a non-invasive approach for monitoring plasma parameters such as the electron temperature and density inside a radio-frequency (RF) plasma nitridation device using optical emission spectroscopy (OES) in conjunction with multivariate data analysis. Instead of relying on a theoretical model of the plasma emission to extract plasma parameters from the OES, an empirical correlation was established on the basis of simultaneous OES and other diagnostics. Additionally, we developed a machine learning (ML)-based virtual metrology model for real-time Te and ne monitoring in plasma nitridation processes using an in situ OES sensor. The results showed that the prediction accuracy of electron density was 97% and that of electron temperature was 90%. This method is especially useful in plasma processing because it provides in-situ and real-time analysis without disturbing the plasma or interfering with the process.

scholarly journals PARAMETERS OF HYDROGEN PLASMA STREAMS IN QSPA-M AND THEIR DEPENDENCE ON EXTERNAL MAGNETIC FIELD

2021 ◽  
pp. 61-64
Author(s):  
M.S. Ladygina ◽  
Yu.V. Petrov ◽  
D.V. Yeliseev ◽  
V.A. Makhlai ◽  
N.V. Kulik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Hydrogen Plasma ◽  
Experimental Studies ◽  
Optical Emission ◽  
Plasma Electron ◽  
Plasma Stream ◽  
Visible Radiation ◽  
Order Of Magnitude ◽  
Plasma Electron Density

Present experimental studies are aimed at analysis of hydrogen plasma stream parameters in various working regimes of QSPA-M operation. Temporal distributions of plasma electron density are reconstructed with optical emission spectroscopy. The magnetic field influence on plasma streams parameters is analyzed. It is shown that in regimes with additional magnetic field the plasma electron density increases by an order of magnitude in comparison with a density value without magnetic field. The plasma velocity and energy density parameters as well as their temporal behaviors were estimatedin different operating regimes of QSPA-M facility. Features of plasma visible radiation were analyzed. This information is important for QSPA-M applications in experiments on interaction of powerful plasma streams with material surfaces.

scholarly journals Diagnostics of low-pressure capacitively coupled RF discharge argon plasma

2019 ◽  
Vol 13 (27) ◽  
pp. 76-82
Author(s):  
Kadhim A. Aadim
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Langmuir Probe ◽  
Gas Flow ◽  
Low Pressure ◽  
Gas Pressure ◽  
Rf Discharge ◽  
Electrode Gap ◽  
Probe Characteristic ◽  
Capacitively Coupled

Low-pressure capacitively coupled RF discharge Ar plasma has been studied using Langmuir probe. The electron temperature, electron density and Debay length were calculated under different pressures and electrode gap. In this work the RF Langmuir probe is designed using 4MHz filter as compensation circuit and I-V probe characteristic have been investigated. The pressure varied from 0.07 mbar to 0.1 mbar while electrode gap varied from 2-5 cm. The plasma was generated using power supply at 4MHz frequency with power 300 W. The flowmeter is used to control Argon gas flow in the range of 600 standard cubic centimeters per minute (sccm). The electron temperature drops slowly with pressure and it's gradually decreased when expanding the electrode gap. As the gas pressure increases, the plasma density rises slightly at low gas pressure while it drops little at higher gas pressure. The electron density decreases rapidly with expand distances between electrodes.

scholarly journals Pulsating aurora and cosmic noise absorption associated with growth-phase arcs

2018 ◽  
Vol 36 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Derek McKay ◽  
Noora Partamies ◽  
Juha Vierinen
Keyword(s):  
Growth Phase ◽  
Optical Emission ◽  
Border Region ◽  
Emission Region ◽  
Expansion Phase ◽  
Phase Dynamics ◽  
Noise Absorption ◽  
Initial Stage ◽  
Cosmic Noise

Abstract. The initial stage of a magnetospheric substorm is the growth phase, which typically lasts 1–2 h. During the growth phase, an equatorward moving, east–west extended, optical auroral arc is observed. This is called a growth-phase arc. This work aims to characterize the optical emission and riometer absorption signatures associated with growth-phase arcs of isolated substorms. This is done using simultaneous all-sky camera and imaging riometer observations. The optical and riometric observations allow determination of the location of the precipitation within growth-phase arcs of low- (<10  keV) and high- (> 10 keV) energy electrons, respectively. The observations indicate that growth-phase arcs have the following characteristics: The peak of the cosmic noise absorption (CNA) arc is equatorward of the optical emission arc. This CNA is contained within the region of diffuse aurora on the equatorward side. Optical pulsating aurora are seen in the border region between the diffuse emission region on the equatorward side and the bright growth-phase arc on the poleward side. CNA is detected in the same region. There is no evidence of pulsations in the CNA. Once the equatorward drift starts, it proceeds at constant speed, with uniform separation between the growth-phase arc and CNA of 40±10 km. Optical pulsating aurora are known to be prominent in the post-onset phase of a substorm. The fact that pulsations are also seen in a fairly localized region during the growth phase shows that the substorm expansion-phase dynamics are not required to closely precede the pulsating aurora. Keywords. Ionosphere (auroral ionosphere)

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