Resonance Cones in the Field Pattern of a Short Antenna in an Anisotropic Plasma

Fisher, R. K.; Gould, R. W.

doi:10.1103/physrevlett.22.1093

Cited by 167 publications

(103 citation statements)

References 7 publications

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“…(12). The curves are generally well described by the effective medium approximation (11). However, an intermediate "mixed" regime is possible for α 0,zz ≈ −1.3a 3 /(4π) (blue dashed curve), when two Bloch modes with hyperbolic and elliptic dispersion coexist in the structure.…”

Section: A Isofrequency Curvesmentioning

confidence: 91%

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Microscopic model of Purcell enhancement in hyperbolic metamaterials

et al. 2012

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We study theoretically a dramatic enhancement of spontaneous emission in metamaterials with the hyperbolic dispersion modeled as a cubic lattice of anisotropic resonant dipoles. We analyze the dependence of the Purcell factor on the source position in the lattice unit cell and demonstrate that the optimal emitter position to achieve large Purcell factors and Lamb shifts are in the local field maxima. We show that the calculated Green function has a characteristic cross-like shape, spatially modulated due to structure discreteness. Our basic microscopic theory provides fundamental insights into the rapidly developing field of hyperbolic metamaterials.

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Section: A Isofrequency Curvesmentioning

confidence: 91%

“…5b). The distribution has a distinct cross-like shape, typical for hyperbolic medium [8,11]. In the elliptic case, the only field singularity is that at the origin R = |r − r 0 | = 0.…”

Section: B Green Functionmentioning

confidence: 97%

Microscopic model of Purcell enhancement in hyperbolic metamaterials

et al. 2012

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“…The LH waves launched from the grill antenna are expected to propagate toward the probe head on the first pass along and nearly parallel to the background magnetic field lines due to their electrostatic nature [24]. The power spectrum launched with the grill antenna has a finite width in the n || space due to a finite number of radiating elements along the toroidal direction.…”

mentioning

confidence: 99%

Measurements of the parallel wavenumber of lower hybrid waves in the scrape-off layer of a high-density tokamak

Baek

Wallace

Shinya³

et al. 2016

Physics of Plasmas

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In lower hybrid current drive (LHCD) experiments on tokamaks, the parallel wavenumber of lower hybrid waves is an important physics parameter that governs the wave propagation and absorption physics. However, this parameter has not been experimentally well-characterized in the present-day high density tokamaks, despite the advances in the wave physics modeling. In this paper, we present the first measurement of the dominant parallel wavenumber of lower hybrid waves in the scrape-off layer (SOL) of the Alcator C-Mod tokamak with an array of magnetic loop probes. The electric field strength measured with the probe in typical C-Mod plasmas is about one-fifth of that of the electric field at the mouth of the grill antenna. The amplitude and phase responses of the measured signals on the applied power spectrum are consistent with the expected wave energy propagation. At higher density, the observed k|| increases for the fixed launched k||, and the wave amplitude decreases rapidly. This decrease is correlated with the loss of LHCD efficiency at high density, suggesting the presence of loss mechanisms. Evidence of the spectral broadening mechanisms is observed in the frequency spectra. However, no clear modifications in the dominant k|| are observed in the spectrally broadened wave components, as compared to the measured k|| at the applied frequency. It could be due to (1) the probe being in the SOL and (2) the limited k|| resolution of the diagnostic. Future experiments are planned to investigate the roles of the observed spectral broadening mechanisms on the LH density limit problem in the strong single pass damping regime.

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“…However, to the authors' knowledge, the integral equation formulation for a magnetized plasma given by (8) and (9) is new. Of course, the literature is vast, spanning more than 50 years, and it is possible that this result may have been derived previously in work unknown to the present author.…”

Section: Formulation As An Integral Equationmentioning

confidence: 99%