Structure of Langmuir and electromagnetic collapsing wave packets in two-dimensional strong plasma turbulence

Journal Article · Sun Jul 15 04:00:00 EDT 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2749495· OSTI ID:20975151

Alinejad, H; Robinson, P A; Cairns, I H; Skjaeraasen, O; Sobhanian, S ^[1]

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1. School of Physics, University of Sydney, NSW 2006, Sydney (Australia) and Faculty of Physics, Tabriz University, Tabriz 51664 (Iran, Islamic Republic of)

Nucleating and collapsing wave packets relevant to electromagnetic strong plasma turbulence are studied theoretically in two dimensions. Model collapsing Langmuir and transverse potentials are constructed as superpositions of approximate eigenstates of a spherically symmetric density well. Electrostatic and electromagnetic potentials containing only components with azimuthal quantum numbers m=0, 1, 2 are found to give a good representation of the electric fields of nucleating collapsing wave packets in turbulence simulations. The length scales of these trapped states are related to the electron thermal speed v{sub e} and the length scale of the density well. It is shown analytically that the electromagnetic trapped states change with v{sub e} and that for v{sub e} < or approx. 0.17c they are delocalized, in accord with recent simulations. In this case, the Langmuir mode collapses independently, as in electrostatic plasma turbulence. For v{sub e} > or approx. 0.17c, the Langmuir and transverse modes remain coupled during collapse, with autocorrelation lengths in a constant ratio. An investigation of energy transfer to packets localized in density wells shows that the strongest power transfer to the nucleating state occurs for Langmuir waves. Energy transitions between different trapped and free states for collapsing wave packets are studied, and the transition rate from trapped Langmuir to free plane electromagnetic waves is calculated and related to the emission of electromagnetic waves at the plasma frequency.

• OSTI ID: 20975151
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
EIGENSTATES
ELECTRIC FIELDS
ELECTROMAGNETIC RADIATION
ELECTRONS
EMISSION
ENERGY TRANSFER
LANGMUIR FREQUENCY
PLASMA
PLASMA DENSITY
PLASMA SIMULATION
PLASMA WAVES
POTENTIALS
QUANTUM NUMBERS
TRAPPING
TURBULENCE
TWO-DIMENSIONAL CALCULATIONS
WAVE PACKETS