Propagation and absorption of ion hybrid waves in a weakly inhomogeneous plasma laser. I

Glagolev, V. M.

doi:10.1088/0032-1028/14/3/006

Cited by 7 publications

(2 citation statements)

References 5 publications

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“…[2], this paper removes most of the speculation concerning the accessibility to the lower-hybrid resonance and brings us closer to a complete understanding of this important problem. Accessibility to the lower-hybrid resonance may have an important bearing on the heating of thermonuclear plasmas using ion-cyclotron harmonic waves if, as pointed out by Glagolev [10], propagation from the plasma edge till the hybrid layer is not materially affected by the inclusion of finite-temperature effects.…”

Section: Discussionmentioning

confidence: 99%

Slow-wave coupling to the lower-hybrid resonance

Puri

Tutter

1974

Nucl. Fusion

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Previously, it has been shown that in a cold, inhomogeneous, magnetized plasma half-space the lower-hybrid resonance is accessible to the transverse-magnetic (TM) plane waves incident on the vacuum-plasma interface at an approximately grazing incidence, provided that at the hybrid layer ωpe/ωce ≲ 0.4. In this paper, these results are extended to the slow-wave case when nz, the refractive index in the static magnetic field direction, exceeds unity. It is found that the plasma is indeed accessible to the slow waves if Golant's accessibility criterion nz > 1 + (ωpe/ωce)2 is satisfied. The following recommendations can be made for coupling r.f. energy to the lower-hybrid resonance: (i) if ωpe/ωce ≲ 0.4, efficient coupling is possible by launching TEM-like waves on the plasma column, (ii) if ωpe/ωce ≳ 0.4 and if the transverse machine dimensions exceed the r.f. vacuum wavelength, it is possible to couple TM waves using passive slow-wave structures inside the machine walls, (iii) if ωpe/ωce ≳ 0.4, but for smaller machine dimensions, recourse must be taken to transverse-electric slow-wave coupling with current-carrying coils of appropriate periodicity . If, as was pointed out by Glagolev, propagation from the plasma edge to the hybrid layer is not materially affected by the inclusion of finite-temperature effects, by far the most elegant solution (with potential application to thermonuclear plasmas) for coupling r.f. energy from the second to the twentieth ion-cyclotron harmonic waves is by launching TEM-like waves in the coaxial waveguide formed by the plasma columnand the containing walls.

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Section: Discussionmentioning

confidence: 99%

Slow-wave coupling to the lower-hybrid resonance

Puri

Tutter

1974

Nucl. Fusion

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“…Since the ion Larmor radius here is much larger than the wavelength (k ⊥ ρ i = √ 2λ i 1), the ions stream almost freely within a wavelength, thus absorb the wave energy through only the ion Landau damping, as described by Glagolev. [35] In the perspective of PI, Eq. ( 15) shows only one decay channel, of which the maximum value locates near ω r = kv ti , somewhere different from ISQM and ICQM.…”

Section: Pi In Different Parameter Regimesmentioning

confidence: 99%

Parametric decay instabilities of lower hybrid waves on CFETR

Zhou¹,

Xiang²,

Gan³

et al. 2022

Chinese Phys. B

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The lower hybrid current drive is a potential candidate for sustaining plasma current in tokamak steady state operations, which could be used in China Fusion Engineering Test Reactor (CFETR) with input power up to a few ten megawatts. Such high input power could trigger the well-known parametric instabilities (PIs) at the plasma edge affecting the propagation and absorption of the lower hybrid pump waves, which is studied in this paper. By analyzing the expression of PI growth rates solved from the nonlinear dispersion relation, it is found that the pressure is the key parameter determining the PI characteristics. Ion sound quasi-mode (ISQM) is the dominant decay channel in the low pressure regime, while the ion cyclotron quasi-mode (ICQM), as well as its harmonics, becomes dominant in the intermediate regime. In the high pressure regime, only one mixed channel is found, which is related to Landau damping by free-streaming ions. Analytical expressions of growth rates of these decay channels are also obtained to show the parameter dependences at different pressure limits. The above analytical results are used to estimate the PIs on a typical profile of CFETR, and verified by corresponding numerical calculations. ICQM is found to be the strongest decay channel with a considerable growth rate for CFETR.

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Accessibility to the lower hybrid resonance

Artico

Spigler

1974

Lett. Nuovo Cimento

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Propagation and absorption of ion hybrid waves in a weakly inhomogeneous plasma laser. I

Cited by 7 publications

References 5 publications

Slow-wave coupling to the lower-hybrid resonance

Slow-wave coupling to the lower-hybrid resonance

Parametric decay instabilities of lower hybrid waves on CFETR

Accessibility to the lower hybrid resonance

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