59,255 research outputs found
Space plasma physics research
During the course of this grant, work was performed on a variety of topics and there were a number of significant accomplishments. A summary of these accomplishments is included. The topics studied include empirical model data base, data reduction for archiving, semikinetic modeling of low energy plasma in the inner terrestrial magnetosphere and ionosphere, O(+) outflows, equatorial plasma trough, and plasma wave ray-tracing studies. A list of publications and presentations which have resulted from this research is also included
Research in plasma physics
Three aspects of barium ion cloud dynamics are discussed. First, the effect of the ratio of ion cloud conductivity to background ionospheric conductivity on the motion of barium ion clouds is investigated and compared with observations of barium ion clouds. This study led to the suggestion that the conjugate ionosphere participates in the dynamics of barium ion clouds. Second, analytic work on the deformation of ion clouds is presented. Third, a linearized stability theory was extended to include the effect of the finite extent of an ion cloud, as well as the effect of the ratio of ion cloud to ionospheric conductivities. The stability properties of a plasma with contra-streaming ion beams parallel to a magnetic field are investigated. The results are interpreted in terms of parameters appropriate for collisionless shock waves. It is found that this particular instability can be operative only if the up-stream Alfven Mach number exceeds 5.5
Mini-Conference on Hamiltonian and Lagrangian Methods in Fluid and Plasma Physics
A mini-conference on Hamiltonian and Lagrangian methods in fluid and plasma
physics was held on November 14, 2002, as part of the 44th meeting of the
Division of Plasma Physics of the American Physical Society. This paper
summarizes the material presented during the talks scheduled during the
Mini-Conference, which was held to honor Allan Kaufman on the occasion of his
75th birthday.Comment: 14 pages, conference summar
Plasma physics in clusters of galaxies
Clusters of galaxies are the largest self-gravitating structures in the
universe. Each cluster is filled with a large-scale plasma atmosphere, in which
primordial matter is mixed with matter that has been processed inside stars.
This is a wonderful plasma physics laboratory. Our diagnostics are the data we
obtain from X-ray and radio telescopes. The thermal plasma is a strong X-ray
source; from this we determine its density and temperature. Radio data reveal a
relativistic component in the plasma, and first measurements of the
intracluster magnetic field have now been made. Energization of the particles
and the field must be related to the cosmological evolution of the cluster. The
situation is made even richer by the few galaxies in each cluster which host
radio jets. In these galaxies, electrodynamics near a massive black hole in the
core of the galaxy lead to a collimated plasma beam which propagates from the
nucleus out to supergalactic scales. These jets interact with the cluster
plasma to form the structures known as radio galaxies. The interaction disturbs
and energizes the cluster plasma. This complicates the story but also helps us
understand both the radio jets and the cluster plasma.Comment: 12 pages, 6 figures, 3 in color. Invited review, to appear in Physics
of Plasmas, May 2003. After publication it can be found at
http://ojps.aip.org/po
Nonlinear aspects of quantum plasma physics
Dense quantum plasmas are ubiquitous in planetary interiors and in compact
astrophysical objects, in semiconductors and micro-mechanical systems, as well
as in the next generation intense laser-solid density plasma interaction
experiments and in quantum x-ray free-electron lasers. In contrast to classical
plasmas, one encounters extremely high plasma number density and low
temperature in quantum plasmas. The latter are composed of electrons, positrons
and holes, which are degenerate. Positrons (holes) have the same (slightly
different) mass as electrons, but opposite charge. The degenerate charged
particles (electrons, positrons, holes) follow the Fermi-Dirac statistics. In
quantum plasmas, there are new forces associated with i) quantum statistical
electron and positron pressures, ii) electron and positron tunneling through
the Bohm potential, and iii) electron and positron angular momentum spin.
Inclusion of these quantum forces provides possibility of very high-frequency
dispersive electrostatic and electromagnetic waves (e.g. in the hard x-ray and
gamma rays regimes) having extremely short wavelengths. In this review paper,
we present theoretical backgrounds for some important nonlinear aspects of
wave-wave and wave-electron interactions in dense quantum plasmas.
Specifically, we shall focus on nonlinear electrostatic electron and ion plasma
waves, novel aspects of 3D quantum electron fluid turbulence, as well as
nonlinearly coupled intense electromagnetic waves and localized plasma wave
structures. Also discussed are the phase space kinetic structures and
mechanisms that can generate quasi-stationary magnetic fields in dense quantum
plasmas. The influence of the external magnetic field and the electron angular
momentum spin on the electromagnetic wave dynamics is discussed.Comment: 42 pages, 20 figures, accepted for publication in Physics-Uspekh
Solar Physics - Plasma Physics Workshop
A summary of the proceedings of a conference whose purpose was to explore plasma physics problems which arise in the study of solar physics is provided. Sessions were concerned with specific questions including the following: (1) whether the solar plasma is thermal or non-themal; (2) what spectroscopic data is required; (3) what types of magnetic field structures exist; (4) whether magnetohydrodynamic instabilities occur; (5) whether resistive or non-magnetohydrodynamic instabilities occur; (6) what mechanisms of particle acceleration have been proposed; and (7) what information is available concerning shock waves. Very few questions were answered categorically but, for each question, there was discussion concerning the observational evidence, theoretical analyses, and existing or potential laboratory and numerical experiments
CfA Plasma Talks
Notes from a series of 13 one hour (or more) lectures on Plasma Physics given
to Ramesh Narayan' research group at the Harvard-Smithsonian Center for
Astrophysics, between January and July 2012.
Lectures 1 to 5 cover various key Plasma Physics themes. Lectures 6 to 12
mainly go over the Review Paper on "Multidimensional electron beam-plasma
instabilities in the relativistic regime" [\emph{Physics of Plasmas}
\textbf{17}, 120501 (2010)]. Lectures 13 talks about the so-called Biermann
battery and its ability to generate magnetic fields from scratch.Comment: 58 pages, 21 figure
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