The Electrical Conductivity of an Ionized Gas

Cohen, Robert S.; Spitzer, Lyman; Routly, Paul McR.

doi:10.1103/physrev.80.230

Cited by 412 publications

(212 citation statements)

References 10 publications

Supporting

Mentioning

200

Contrasting

Unclassified

Order By: Relevance

“…The description is based on the Frost mixture rule. 39 In the limit of a fully singly ionized plasma, this mixture rule converges to the Spitzer-Härm value SH of 40 with the electron temperature T e in kelvins and ln ⌳ the Coulomb logarithm. For a nonfully singly ionized plasma, the collisions between electrons and neutrals, viz., N and N 2 , cause the conductivity to be lower.…”

Section: ͑13͒mentioning

confidence: 84%

Theoretical investigation of a photoconductively switched high-voltage spark gap

Broks

Hendriks

Brok

et al. 2006

Journal of Applied Physics

View full text Add to dashboard Cite

In this contribution, a photoconductively switched high-voltage spark gap with an emphasis on the switching behavior is modeled. It is known experimentally that not all of the voltage that is present at the input of the spark gap is switched, but rather a fraction of it drops across the spark gap. This voltage drop depends on the voltage that is present at the input of the spark gap with higher voltages resulting in a smaller drop. We have investigated two possible causes of this: the cathode fall and the resistance of the plasma arc. Using an analytical model of the cathode fall, we have established that the cathode fall can be excluded as the cause of the observed voltage drop. A one-dimensional, time-dependent non-local thermal equilibrium fluid model of the arc plasma has been made. Using this model, the plasma properties have been analyzed for various values of the switched current with emphasis on the conductivity. A good qualitative match between the observed and the simulated dissipation in the gap was found. This indicates that the finite arc resistance is the cause of the observed voltage drop.

show abstract

Section: ͑13͒mentioning

confidence: 84%

Theoretical investigation of a photoconductively switched high-voltage spark gap

Broks

Hendriks

Brok

et al. 2006

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The laser energy deposition via inverse bremsstrahlung is calculated with a three-dimensional ray tracing package. The electron thermal conduction is treated by the Spitzer-Härm model [30,31]with a flux limiter [32] which is usually taken as 0.08 in our simulations. The thermodynamic quantities are derived either from the ideal gas model or from data of realistic equation of state.…”

Section: Code and Modelmentioning

confidence: 99%

Foam Au driven by 4ω–2ω ignition laser pulse for inertial confinement fusion

Lan

Song

2017

Physics of Plasmas

View full text Add to dashboard Cite

Green light (2ω) has the potential to drive ignition target for laser fusion with significantly more energy than blue light (3ω) and a relatively higher damage threshold for the optic components in the final optic assembly, but it has issues of a relatively low laser to x-ray conversion efficiency and a hard x-ray spectrum as compared to 3ω. In this paper, we propose to drive a foam hohlraum wall with an ignition laser pulse by taking a 4ω laser at the pre-pulse and a 2ω laser at the main-pulse, called as 4ω -2ω ignition pulse. This novel design has the following advantages: (1) benefiting from 2ω of its relatively high energy output and low damage threshold during main-pulse; (2) benefiting from foam in its relatively high laser to x-ray conversion efficiency and relatively low M-band fraction in re-emission; (3) benefiting from 4ω of its low LPI during pre-pulse. From our 1D simulations with Au material, the laser to x-ray conversion in a foam driven by 4ω -2ω pulse has an increase of 28% as compared to a solid target driven by 3ω with the same pulse shape. The relatively thin optical depth of foam is one of the main reasons for the increase of laser to x-ray conversion efficiency inside a foam target.

show abstract

“…The temperature gradient r e is estimated numerically from the ion line data. The Knudsen number 2k e r log e (Guio et al, 1998) where k e is the electron mean free path, is a parameter used in the Spitzer function (Cohen et al, 1950;Spitzer and HaÈ rm, 1953) to represent the electron ambient distribution function in presence of a temperature gradient.…”

Section: The Datamentioning

confidence: 99%

“…This heat¯ow correction term behaves as an additional mean Doppler velocity that arti®cially increases the di erence of the Doppler shifts of the plasma lines. Guio et al (1998) showed that the heat¯ow e ect was underestimated for UHF radars by comparing the heat¯ow approximation of the dispersion relation with a full numerical estimation of the dielectric response function using the Spitzer velocity distribution for a plasma with a temperature gradient (Cohen et al, 1950;Spitzer and HaÈ rm, 1953). It was also shown that for VHF radars, suprathermal electrons would contribute to modify the dielectric response function and thus the Doppler frequency of the plasma lines.…”

Section: Introductionmentioning

confidence: 99%

Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines

Guio

Lilensten

1999

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. In an incoherent scattering radar experiment, the spectral measurement of the so-called up-and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geometry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage of photoelectrons produced by the solar EUV of the total electron population can excite or damp these Langmuir waves above the thermal equilibrium, resulting in an enhancement of the intensity of the lines above the thermal level. The presence of photo-electrons also modi®es the dielectric response function of the plasma from the Maxwellian and thus in¯uences the Doppler frequency of the plasma lines. In this paper, we present a high time-resolution plasma-line data set collected on the EISCAT VHF radar. The analysed data are compared with a model that includes the e ect of a suprathermal electron population calculated by a transport code. By comparing the intensity of the analysed plasma lines data to our model, we show that two sharp peaks in the electron suprathermal distribution in the energy range 20±30 eV causes an increased Landau damping around 24.25 eV and 26.25 eV. We have identi®ed these two sharp peaks as the e ect of the photoionisation of N 2 and O by the intense¯ux of monochromatic HeII radiation of wavelength 30.378 nm (40.812 eV) created in the chromospheric network and coronal holes. Furthermore, we see that what would have been interpreted as a mean Doppler drift velocity for a Maxwellian plasma is actually a shift of the Doppler frequency of the plasma lines due to suprathermal electrons.

show abstract

The Electrical Conductivity of an Ionized Gas

Cited by 412 publications

References 10 publications

Theoretical investigation of a photoconductively switched high-voltage spark gap

Theoretical investigation of a photoconductively switched high-voltage spark gap

Foam Au driven by 4ω–2ω ignition laser pulse for inertial confinement fusion

Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines

Contact Info

Product

Resources

About