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Results for “collisional plasma”

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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Emission Process II: Collisional Plasmas

Covered are the basic atomic processes that are important in X-ray emitting plasmas; collisional excitation/ionization, photoexitation/ionization, radiative decay and so on.

Smith, Randall K.↗
NASA NTRS2013

Discrete Kinetic Eigenmode Spectra of Electron Plasma Oscillations in Weakly Collisional Plasma: A Numerical Study

It has been demonstrated that in the presence of weak collisions, described by the Lenard-Bernstein collision operator, the Landau-damped solutions become true eigenmodes of the system and constitute a complete set. We present numerical results from an Eulerian Vlasov code that incorporates the Lenard-Bernstein collision operator. The effect of the collisions on the numerical recursion phenomenon seen in Vlasov codes is discussed. The code is benchmarked against exact linear eigenmode solutions in the presence of weak collisions, and a spectrum of Landau-damped solutions is determined within the limits of numerical resolution. Tests of the orthogonality and the completeness relation are presented.

Kinetic Eigenmode Spectra↗
NASA NTRS1974

The electromagnetic interchange mode in a partially ionized collisional plasma

A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interchange mode coupled to the Alfven, acoustic, drift and entropy modes in a partially ionized plasma. The fundamental electromagnetic nature of the interchange model is noted; coupling to the intermediate Alfven mode is strongly stabilizing for finite k sub z. Both ion viscous and ion-neutral stabilization are included, and it was found that collisions destroy the ion finite Larmor radius cutoff at short perpendicular wavelengths.

Hudson, M. K.↗
NASA NTRS1975

The electromagnetic interchange mode in a partly-ionized collisional plasma

A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interchange mode coupled to the Alfven, acoustic, drift, and entropy modes in a partially ionized plasma. The fundamental electromagnetic nature of the interchange mode is noted: coupling to the intermediate Alfven mode is strongly stabilizing for finite perturbations of the magnetic field. Both ion-viscous and ion-neutral stabilization are included; and it is found that collisions destroy the FLR (finite Larmor radius) cutoff at short perpendicular wavelengths.

Hudson, M. K.↗
NASA NTRS1976

Lagrangian density for collisional plasma

For the purpose of deriving appropriate Lagrangians for plasma equations that include effects of energy loss, the paper examines the inverse problem of the calculus of variations for systems of first- and second-order quasi-linear partial differential equations. This results in convenient forms of the sufficient conditions under which the given differential equations are Euler-Lagrange equations of a Lagrangian. These conditions are then applied to determine the necessary transformation that converts equations, apparently not already in it, into Euler-Lagrange form. The appropriate Lagrangian for a warm collisional plasma is obtained, and the Lagrangian is derived for a resistive transmission line.

Peng, Y.-K. M.↗
NASA NTRS1991

Nonlinear penetration of whistler pulses into collisional plasmas via conductivity modifications

A strong electromagnetic impulse (about 0.2 microsec) with central frequency in the whistler-wave regime is applied to a large laboratory plasma dominated by Coulomb collisions. Local electron heating at the antenna and transport along B0 create a channel of high conductivity along which the whistler pulse penetrates with little damping. Because of its rapid temporal evolution, this new form of modulational instability does not involve ducting by density gradients which require ion time scales to develop.

Urrutia, J. M.↗