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Rocket observations of upper atmospheric winds, electron density, electron temperature, and neutral temperature in auroral region with Langmuir probes
Electron density, electron temperature, and earth magnetic field above Fort Churchill from rocket measurements
Many features of Herbig-Haro objects can be reproduced using a kinematical bow shock model. We use the model to generate position-velocity (PV) diagrams of flux in H-alpha (O I) lambda lambda 6300+63, (S II) lambda lambda 6716+31, (O III) lambda lambda 4959+5007, and (C I) lambda lambda 9823+50, line ratios of (O I)/H-alpha, (O I)/(S II), (S II)/H-alpha, H-alpha(S II), and (O III)/H-alpha, electron density N(sub e), and electron temperature T(sub e). We show how position-velocity diagrams of N(sub e) and flux vary with shock velocity. By matching the diagrams from single lines, the line ratios, and N(sub e) with observations, we determined a narrow range of shock parameters for HH 1F, 2(A' + H), and 43 (B + C). We model the N(sub e) features of HH 2(A' + H) as a superposition of two bowshocks. We also show that the effects of slight misalignments of the two diagrams to be divided can produce artifacts in the line ratios and N(sub e) which obliterate the physical features. We show that N(sub e) in HH 1 can only be explained using the kinematical model by taking these misalignments into account.
Lower E region recombination coefficients from electron density and flux measurements in glow aurora by Nike-Apache rocket
Electron density and temperature in inviscid flow and nozzle-wall boundary layer, measured with constant bias-voltage and swept-voltage RAM probes
Many features of Herbig-Haro objects can be reproduced using a kinematical bow shock model.
Here we have measured two-dimensional electron systems bound to a thin helium film supported by a metallic substrate. We report on our measurement of electron density obtained via a Kelvin probe technique. The underlying metallic substrate is an amorphous metallic alloy (TaWSi), which can support large uniform densities due to its low surface roughness and homogeneous work function. We find that this substrate is able to support high enough densities that the electrons are expected to be Fermi-degenerate.
Electron density and temperature distribution in boundary layer flow of reflected shock tunnel conical nozzle
Mathematical model for prediction of electron density at equilibrium
Ionospheric electron density profiles obtained by the cw propagation technique and by rf impedance probe techniques
Langmuir and current probe measurements of ion thrustor beam, and resulting transverse and longitudinal profiles of electron and ion densities
Spatial and temporal models used to study response of ionospheric electron density to change of electron temperature
Spectroscopic electron density diagnostics have been developed for interpretation of UV, EUV, and X-ray emission line spectra of solar and other astrophysical plasmas, and tokamak plasmas. In principle, accurate electron densities can be determined. However, in practice, a number of difficulties arise with respect to the determination of very accurate electron densities in the 1100-3000 A region. The present study has the objective to investigate one of these difficulties, taking into account the effect on line ratios produced by a source composed of several regions of substantially different densities, all at the same temperature. The study is in particular concerned with a source in which small high density knots are embedded in low-density plasma. Attention is given to line ratios involving the O IV multiplet near 1400 A, obtained from the spectrum of a surge observed outside the solar limb.
Two-dimensional electrostatic particle-in-cell simulations are used to study the early time evolution of electron depletions and negative ion clouds produced during electron attachment chemical releases in the ionosphere. The simulation model considers the evolution in the plane perpendicular to the magnetic field and a three-species plasma that contains electrons, positive ions, and also heavy negative ions that result as a by-product of the electron attachment reaction. The early time evolution (less than the negative ion cyclotron period) of the system shows that a negative charge surplus initially develops outside of the depletion boundary as the heavy negative ions move across the boundary. The electrons are initially restricted from moving into the depletion due to the magnetic field. An inhomogenous electric field develops across the boundary layer due to this charge separation. A highly sheared electron flow velocity develops in the depletion boundary due to E x B and Delta-N x B drifts that result from electron density gradients and this inhomogenous electric field. Structure eventually develops in the depletion boundary layer due to low-frequency electrostatic waves that have growth times shorter than the negative ion cyclotron period. It is proposed that these waves are most likely produced by the electron-ion hybrid instability that results from sufficiently large shears in the electron flow velocity.
Electron beam density probe calibration for earth atmospheric reentry vehicles communication
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Abstract Recent studies of secondary electron (SE) emission in scanning transmission electron microscopes suggest that material’s properties such as electrical conductivity, connectivity, and work function can be probed with atomic scale resolution using a technique known as secondary electron e-beam-induced current (SEEBIC). Here, we apply the SEEBIC imaging technique to a stacked 2D heterostructure device to reveal the spatially resolved electron density of an encapsulated WSe 2 layer. We find that the double Se lattice site shows higher emission than the W site, which is at odds with first-principles modelling of valence ionization of an isolated WSe 2 cluster. These results illustrate that atomic level SEEBIC contrast within a single material is possible and that an enhanced understanding of atomic scale SE emission is required to account for the observed contrast. In turn, this suggests that, in the future, subtle information about interlayer bonding and the effect on electron orbitals could be directly revealed with this technique.