Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ELECTRON TEMPERATURE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Determination of electron temperature in a penning discharge by the helium line ratio method

The helium line ratio technique was used to determine electron temperatures in a toroidal steady-state Penning discharge operating in helium. Due to the low background pressure, less than .0001 torr, and the low electron density, the corona model is expected to provide a good description of the excitation processes in this discharge. In addition, by varying the Penning discharge anode voltage and background pressure, it is possible to vary the electron temperature as measured by the line ratio technique over a wide range (10 to 100+ eV). These discharge characteristics allow a detailed comparison of electron temperatures measured from different possible line ratios over a wide range of temperatures and under reproducible steady-state conditions. Good agreement is found between temperatures determined from different neutral line ratios, but use of the helium ion line results in a temperature systematically 10 eV high compared to that from the neutral lines.

Richardson, R. W.↗
NASA NTRS2008

Measuring the Electron Temperature in the Corona

We report on an experiment to demonstrate the feasibility of a new method to obtain the electron temperature and flow speed in the solar corona by observing the visible Kcoronal spectrum during the total solar eclipse on 29 March 2006 in Libya. Results show that this new method is indeed feasible, giving electron temperatures and speeds of 1.10 $\pm$ 0.05 MK, 103.0 $\pm$ 92.0 $kmsA{-l}$; 0.98 $\pm$ 0.12 MK, 0.0 + 10.0 $kmsA{-1)s; 0.70 $\pm$ 0.08 MK, 0.0 + 10.0 $kmsA{-l)$ at l.l{\it R)$ {\odot}$ in the solar north, east and west, respectively, and 0.93 $\pm$ 0.12 MK, 0.0 + 10.0 $kmsA{-l}$ at 1.2{\it R}$ {\odot}$ in the solar east. This new technique could be easily used from a space-based platform in a coronagraph to produce two dimensional maps of the electron temperature and bulk flow speed at the base of the solar wind useful for the study of heliospheric structure and space weather.

Davila, Joseph↗
NASA NTRS1994

Hopkins Ultraviolet Telescope determination of the Io torus electron temperature

Sulfur ion emissions from the Io plasma torus observed by the Hopkins Ultraviolet Telescope (HUT) in 1990 December have been analyzed to determine the effective temperature of the exciting electrons. Spectra were obtained with a long slit that extended from 3.1 to 8.7 Jupiter radii R(sub J) on both dawn and dusk torus ansae. The average temperature of electrons exciting S(2+) emissions from the dawn ansa is (4800 +/- 2400) K lower than on the dusk ansa, a dawn-dusk asymmetry comparable in both sign and magnitude to that measured by the Voyager Ultraviolet Spectrograph (UVS) experiment. Emissions from S(2+) ions are generated in a source region with electron temperatures in the range 32,000-56,000 K; S(3+) ion emissions are excited by electrons that average 20,000-40,000 K hotter. This distinct difference suggests that the S(3+) emission source region is spatially separate from the S(2+) source region. Estimated relative aperture filling factors suggest that the S(3+) emissions originate from a region more extended out of the centrifugal plane than the S(2+) emissions.

Hall, D. T.↗
NASA NTRS2020

High Temperature Electronics for Venus Surface Applications: A Summary of Recent Technical Advances

This white paper has a technical focus meant to provide background to those unfamiliar with the challenges of high temperature electronics, and an understanding of why new surface mission concepts are now viable for Venus and other applications. It describes that, for the first time, high temperature electronics have been developed to enable a paradigm change in extended duration Venus surface exploration. This white paper concentrates on the advances made in Silicon Carbide (SiC) integrated circuit (IC) electronics that have matured to a state where a simple long-life scientific probe is feasible for Venus surface operations. These electronics have been demonstrated for more than a year at 500˚C, 60 days in high-fidelity simulated Venus surface conditions chamber, and have been integrated and demonstrated with prototype long-lived scientific observation sensor technology. Continued maturation of these needed high temperature electronics and sensors is ongoing in the Long-Lived In-Situ Solar System Explorer (LLISSE) project to provide an operational system including sensor control and operation, signal processing, power management, and communications in the early part of the 2020’s. A key focus of this work includes increasing the complexity and decreasing the power consumption of the ICs which will pave the way to enhanced capabilities, such as long-duration Venus seismic measurements. Other IC development efforts include high temperature memory, terrestrial based characterization of volcanic magma, and development of a simple microprocessor. This electronics has also shown to have exceptionally high radiation tolerance, and thus have relevance for a broad range of solar system exploration. Although presently at the level of complexity of 1970-1980 silicon-based electronics, such electronics can enable breakthroughs in Venus planetary exploration akin to 1970s-launched planetary exploration successes (such as Viking and Voyager).

High temperature Electronics↗
DOE OSTI2025

Experimental demonstration of real-time electron temperature profile control in DIII-D

Future tokamak reactor operation will require the ability to maintain a given plasma scenario for extended periods of time. This will necessitate the capability to react to changes in the plasma state and return the plasma to the target scenario; the principal method to achieve this is through feedback control. Thus, it is necessary to develop and test feedback controllers for the plasma profiles that define a target scenario. In this work, a feedback controller for the electron temperature (Te) profile is tested experimentally in DIII-D. This experiment relied on the ability to ascertain the electron temperature profile in real time, which was achieved using an observer algorithm. The observer relies on both diagnostic data and a predictive model of the electron temperature profile evolution; this predictive model includes contributions from neural network surrogate models. Because of these dependencies, a number of capabilities needed to be added to the real-time PCS for DIII-D in order to support the Te profile control experiment. The neural network surrogates needed to be integrated into the PCS to be called in real time. An observer algorithm for the Te profile needed to be added and connected to the Thomson scattering system to allow access to the current state of the profile in real time. When tested, the observer was shown to produce Te profiles that are consistent with the shape of the Thomson scattering data while rejecting much of the noise in the diagnostic data. Finally, the controller itself was tested in real time. This experiment showed that the controller is capable of tracking the electron temperature target at locations across the spatial profile.

Morosohk, Shira [Oak Ridge Associated Universities↗
NASA NTRS1973

Simultaneous in situ electron temperature comparisons using Alouette 2 probe and plasma resonance data

The electron temperatures deduced from Alouette 2 diffuse resonance observations are compared with the temperature obtained from the Alouette 2 cylindrical electrostatic probe experiment using data from 5 mid-to-high latitude telemetry stations. The probe temperature is consistently higher than the diffuse resonance temperature. The average difference ranged from approximately 10% to 40% with the lower values occurring at the lowest altitudes sampled (near 500 km) and at high latitudes (dip latitude greater than 55 deg), and the larger values occurring at high altitudes and lower latitudes. The discrepancy appears to be of geophysical origin since it is dependent on the location of the data sample. The present observations support the view that the often observed radar backscatter - probe electron temperature discrepancy is also of geophysical origin.

Benson, R. F.↗
NASA NTRS1973

Simultaneous in situ electron temperature comparison of Alouette 2 probe and plasma resonance data.

The electron temperatures deduced from Alouette 2 diffuse resonance observations are compared with the temperatures obtained from the Alouette 2 cylindrical electrostatic probe experiment using data from five mid- to high-latitude telemetry stations. The probe temperature is consistently higher than the diffuse resonance temperature. The average difference ranged from approximately 10% to 40%, the lower values occurring at the lowest altitudes sampled (near 500 km) and at high latitudes (dip latitude greater than 55 deg) and the larger values occurring at higher altitudes and lower latitudes. The discrepancy appears to be of geophysical origin, since it is dependent on the location of the data sample. These observations support the view that the discrepancy often observed between radar backscatter and probe electron temperature is of geophysical origin.

Benson, R. F.↗
NASA NTRS2008

Obtaining Electron Temperatures and Flow Speeds from Thomson Scattered Coronal Emission Observed during the 29 March 2006 Total Solar Eclipse in Libya

An experiment to measure the electron temperature and flow speed in the solar corona by observing the visible K-coronal spectrum was conducted during the total solar eclipse on 29 March 2006 in Libya. New corona1 models accounting for the effect of electron temperature and flow on the resulting K-corona spectrum were used to interpret the observations. Results show electron temperatures of 1.10 +/- 0.05, 0.98 +/- 0.12, and 0.70 +/- 0.08 MK, at l.l{\it R)$-{\odot)$ in the solar north, east and west, respectively, and 0.93 +/- 0.12 MK, at 1.2 R(sub sun) in the solar east. The corresponding outflow speeds obtained from the spectral fit are 103 +/- 92, 0 + 10, 0 + 10, and 0 + 10 km/s. Since the observations are taken only at 1.1 and 1.2 R(sub sun) these velocities , consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working.

Davila, Joseph M.↗
NASA NTRS1978

Microwave diagnostic for the determination of the electron temperature of a low density shock-heated argon plasma

The diffraction, defocusing and beam bending effects of microwaves transmitted through a bounded shock-heated argon plasma with low electron density are investigated with the purpose of developing an accurate method for electron temperature (Te) determination. This report describes the evaluation technique and presents results for an argon plasma with pressure between 3 and 10 torr, and T2 between 5500 and 9500 K. The electron temperature values obtained have a range of uncertainty between -20% and +10% only. The electron temperature is equal or lower by approximately 1000 K in comparison to the heavy particle temperature (T2).

Schneider, C. P.↗
DOE OSTI2025

Separability of microtearing mode and electron temperature gradient turbulence regimes

The separability of microtearing mode (MTM)-dominated and electron temperature gradient (ETG)-driven turbulence regimes is studied with multiscale nonlinear gyrokinetic simulations. The simulations are based on National Spherical Torus Experiment-like, high-confinement mode pedestal parameters, where electromagnetic perturbations are large. Linear analysis indicates a wide scale-separation between the MTM and ETG modes in binormal wavenumber space (perpendicular to the magnetic field line), with no unstable modes at intermediate scales. Likewise, single-scale nonlinear analyses, retaining ion-only or electron-only spatio-temporal scales, produce seemingly well-converged transport states. Surprisingly, the multiscale simulation, which contains both the ion and electron scales, closely follows the transport from the electron-scale simulation. This trend is robust over a wide range of electron temperature gradient. Remarkably, compared to ion-scale simulations, MTM turbulence is significantly reduced at multiscale resolution even when ETG turbulence is low. In this case, traditional ion-scale resolution overestimates the electron energy flux, and it is not possible to accurately simulate the MTM turbulence with separable ion-scale simulations. Here, while the analysis confirms the validity of electron-scale simulations for predicting the electron transport, it also indicates that multiscale simulation may be required for reproducing the turbulence spectrum for systems with coupled MTM-ETG turbulence.

H-mode↗
NASA NTRS1987

Ionospheric electron temperature at solar maximum

Langmuir-probe measurements made at solar maximum from the DE-2 satellite in 1981 and 1982 are used to examine the latitudinal variation of electron temperature at altitudes between 300 and 400 km and its response to 27-day variations of solar EUV. A comparison of these data with models based on solar-minimum measurements from the AE-C suggests that the daytime electron temperature does not change very much during the solar cycle except at low latitudes where a particularly large 27-day variation occurs. It is found that the daytime electron temperature near the F2 peak is more responsive to short-term variations in F10.7 than to any longer-term changes that may occur between solar minimum and maximum.

Brace, L. H.↗