High-frequency heating in Tokamaks

Klíma, Richard

doi:10.1088/0029-5515/11/4/005

Cited by 6 publications

(8 citation statements)

References 10 publications

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“…Ion-ion hybrid absorption has been recognized recently [5][6][7] as likely to play an important role in plasma heating via magnetosonic waves, and Swanson [7] has presented preliminary solutions to the Budden equation [8] governing propagation of a fast wave normally incident on an ion-ion hybrid resonance surface. This paper sets forth in more detail the geometry of the resonance surface in the minor cross-section surface, generalizes the fast wave propagation equation to arbitrary angle of incidence, and examines the fate of energy launched into the short wavelength modes by the conversion processes.…”

Section: Introductionmentioning

confidence: 99%

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

Perkins¹

1977

Nucl. Fusion

248

154

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The ion-ion hybrid resonance can occur at high plarma• densities in tokamaks and thereby absorb energy from the fast magnetosonic mode which would otherwise propagate freely. Ion-cyclotron resonance regions, although they occur in the low density peripheral plasma, can nonetheless cause sufficient absorption to compete with fundamental cyclotron resonance damping by ions. For the ion-ion hybrid resonance it is shown that: (1) The energy absorption occurs via a sequence of mode conversions. (2) A poloidal field component normal to the ion-ion hybrid mode conversion surface strongly influences the mode conversion process so that rough ly equal electron and ion heating occurs in the present proton-deuterium experiments, while solely electron heating is predicted to prevail in deuteriumtritium reactors. (3) The ion-ion hybrid resonance suppresses toroidal eigenmodes. (4) Wave absorption i~ minority fundamental ion-cyclotron heating experiments will be dominated by ion-ion hybrid mode conversion absorption for minority concentrations exceeding roughly 1%.

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Section: Introductionmentioning

confidence: 99%

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

Perkins¹

1977

Nucl. Fusion

248

154

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“…(To excite waves with N N < 1, it is necessary to use periodic systems with large linear dimensions L ||. Note that the excitation of waves with N N = 0 (9 = 7r/2) has-been considered in detail in Refs [1,2,6]. )…”

Section: Z 2 Xmentioning

confidence: 99%

“…The presence in a plasma of two species of ions leads to the occurrence of an additional branch of oscillations and can significantly change the wave propagation conditions in a plasma in the region of frequencies lower than or of the order of the ion cyclotron frequency. The propagation of electromagnetic waves in a multicomponent plasma has been investigated by a number of authors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In Refs [1,2] it was shown that waves propagating perpendicularly to the magnetic field have a singularity at the point of ion-ion hybrid resonance (u =1*)^) lying between the ion cyclotron frequencies.…”

Section: Introductionmentioning

confidence: 99%

“…The behaviour of the refraction index of electromagnetic waves close to the frequency u* WJJ with allowance for the thermal motion of plasma particles was considered in Ref. [4], Theoretical investigations of the possibility of using electromagnetic waves for heating plasma with two ion species were performed in Refs [5][6][7][8]. Such waves were excited and used to heat a plasma in experiments described in Refs [2,[10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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High-frequency heating of plasma with two ion species

1975

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The authors consider the penetration of electromagnetic waves with a frequency of the order of the ion cyclotron frequencies and with a fixed longitudinal wave number k||, so that N|| = k||c/w » 1 deep into an inhomogeneous plasma with two ion species. The propagation of two kinds of waves (fast and slow) with widely differing polarization and transverse refraction index is possible. For both types of waves there is an evanesence region at the plasma periphery.The evanescence region is narrow for slow waves and they easily penetrate the plasma. In a dense plasma they become electrostatic and can reach the ion-ion hybrid resonance region. However, the damping of these waves due to Cherenkov interaction with electrons in a high-temperature plasma is strong and therefore they are not suitable for heating plasma of large dimensions, as they are absorbed at the plasma periphery.The fast waves have a wider evanescence region and can be excited effectively only if N 2 is not too high. These waves can be completely absorbed in the plasma (due to Cherenkov interaction with electrons) if £ ~(vjj/v^)Z e (ii)pja/c)exp(-Z e ) > 1, where a is the plasma radius and Z e = UJ/(^2 k|| v T e ) . Fast waves can also reach the region where they are transformed into slow waves. In this region their damping increases considerably. It is shown that the transformation region in an inhomogeneous plasma with two ion species in a non-uniform magnetic field may be at the centre of the plasma. Fast waves can be used effectively for heating plasma of large dimensions.

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“…Klima et al [8,9] consider the propagation of magnetoacoustic waves perpendicular to the magnetic field in tokama ks.…”

Section: Introductionmentioning

confidence: 99%

Magnetoacoustic Oscillations of a Plasma Containing Two Species of Ions

Jessup

McCarthy

1978

IEEE Trans. Plasma Sci.

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Numerical calculations of linear magnetoacoustic resonant phenomena in a plasma containing two species of ions have been made for a cylindrical plasma with a model which includes the effects of collisional damping and radial non-uniformities in temperature and number density. At sufficiently high temperatures two frequencies are predicted at which magnetoacoustic resonances for the first radial mode will occur. These are expected from considerations of the effects of the ion-ion hybrid resonance.

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High-frequency heating in Tokamaks

Cited by 6 publications

References 10 publications

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

High-frequency heating of plasma with two ion species

Magnetoacoustic Oscillations of a Plasma Containing Two Species of Ions

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