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Title: Propagation of electromagnetic waves in the plasma near electron cyclotron resonance: Undulator-induced transparency

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.1865053· OSTI ID:20736614
; ; ;  [1]
  1. Department of Physics and Institute for Fusion Studies, University of Texas at Austin, One University Station, Austin, Texas 78712 (United States)

Propagation of electromagnetic waves in magnetized plasma near the electron cyclotron frequency can be strongly modified by adding a weak magnetic undulator. For example, both right- and left-hand circularly polarized waves can propagate along the magnetic field without experiencing resonant absorption. This effect of entirely eliminating electron cyclotron heating is referred to as the undulator-induced transparency (UIT) of the plasma, and is the classical equivalent of the well-known quantum mechanical effect of electromagnetically induced transparency. The basics of UIT are reviewed, and various ways in which UIT can be utilized to achieve exotic propagation properties of electromagnetic waves in plasmas are discussed. For example, UIT can dramatically slow down the waves' group velocity, resulting in the extreme compression of the wave energy in the plasma. Compressed waves are polarized along the propagation direction, and can be used for synchronous electron or ion acceleration. Strong coupling between the two wave helicities are explored to impart the waves with high group velocities {partial_derivative}{omega}/{partial_derivative}k for vanishing wave numbers k. Cross-helicity coupling for realistic density and magnetic field profiles are examined using a linearized fluid code, particle-in-cell simulations, and ray-tracing WKB calculations.

OSTI ID:
20736614
Journal Information:
Physics of Plasmas, Vol. 12, Issue 5; Other Information: DOI: 10.1063/1.1865053; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English