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Unidirectional transparent signal injection in finite-difference time-domain electromagnetic codes -application to reflectometry simulations

Journal Article · · Journal of Computational Physics
 [1];  [2];  [3];  [1]
  1. Associacao EURATOM/IST-Centro de Fusao Nuclear, Instituto Superior Tecnico, 1046-001 Lisbon (Portugal)
  2. Laboratoire de Physique des Milieux Ionises et Applications Unite du CNRS 7040, Universite Henri Poincare, Nancy 1, BP 239, 54506 Vandoeuvre Cedex (France)
  3. Associaca o EURATOM/IST-Centro de Fusao Nuclear, Instituto Superior Tecnico, 1046-001 Lisbon (Portugal)

We present a novel numerical signal injection technique allowing unidirectional injection of a wave in a wave-guiding structure, applicable to 2D finite-difference time-domain electromagnetic codes, both Maxwell and wave-equation. It is particularly suited to continuous wave radar-like simulations. The scheme gives an unidirectional injection of a signal while being transparent to waves propagating in the opposite direction (directional coupling). The reflected or backscattered waves (returned) are separated from the probing waves allowing direct access to the information on amplitude and phase of the returned wave. It also facilitates the signal processing used to extract the phase derivative (or group delay) when simulating radar systems. Although general, the technique is particularly suited to swept frequency sources (frequency modulated) in the context of reflectometry, a fusion plasma diagnostic. The UTS applications presented here are restricted to fusion plasma reflectometry simulations for different physical situations. This method can, nevertheless, also be used in other dispersive media such as dielectrics, being useful, for example, in the simulation of plasma filled waveguides or directional couplers.

OSTI ID:
20687219
Journal Information:
Journal of Computational Physics, Journal Name: Journal of Computational Physics Journal Issue: 2 Vol. 203; ISSN JCTPAH; ISSN 0021-9991
Country of Publication:
United States
Language:
English

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