Excitation, propagation, and damping of electron Bernstein waves in tokamaks

Ram, A. K.; Schultz, S. D.

doi:10.1063/1.1289689

Cited by 141 publications

(196 citation statements)

References 15 publications

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“…The optimum X-B process occurs closer to the edge of the plasma than the optimum O-X-B conversion. A more detailed analysis based on a kinetic treatment of the EBW in sheared magnetic fields confirms the basic results of the analysis given above [1,4]. We have also studied the propagation of EBW rays in model NSTX profiles.…”

Section: Excitation and Propagation Of Ebwssupporting

confidence: 54%

“…However, in order for the O mode power not to get reflected back out on the X mode requires that η > 1 [1,4]. From (8) we find that this condition is satisfied when the density scalelength is long.…”

Section: Excitation and Propagation Of Ebwsmentioning

confidence: 76%

“…From ray tracing analysis we find that EBWs are locally and strongly absorbed at the Doppler shifted electron cyclotron resonance or its harmonics [1]. For spherical tokamak plasmas, the location of the EBW energy deposition is significantly different for excitations on or away from the equatorial plane [1].…”

Section: Introductionmentioning

confidence: 99%

“…The resonance power absorption of the X mode at the UHR corresponds to the power mode converted to the EBWs [1]. Since the O mode is completely decoupled from the X mode, if an O mode is excited at the edge its power will be reflected back out at the O mode cutoff located where…”

Section: Excitation and Propagation Of Ebwsmentioning

confidence: 99%

“…For spherical tokamak plasmas, the location of the EBW energy deposition is significantly different for excitations on or away from the equatorial plane [1].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

On electron Bernstein waves in spherical tori

Ram¹,

Decker²,

Peysson

2005

J. Plasma Phys.

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Section: Excitation and Propagation Of Ebwssupporting

confidence: 54%

Section: Excitation and Propagation Of Ebwsmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Excitation and Propagation Of Ebwsmentioning

confidence: 99%

“…For spherical tokamak plasmas, the location of the EBW energy deposition is significantly different for excitations on or away from the equatorial plane [1].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On electron Bernstein waves in spherical tori

Ram¹,

Decker²,

Peysson

2005

J. Plasma Phys.

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Passive Diagnostics

2013

Fusion Plasma Diagnostics With Mm‐Waves

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Magnetically confined hot fusion plasmas emit electromagnetic radiation in a wide spectral range extending from the radio frequency range to the X-ray region. It covers a wavelength range of almost ten orders of magnitude. Each range has its own diagnostic potential. Three generation mechanisms need to be distinguished: (i) the acceleration of electrons and ions in the confining magnetic field, (ii) the acceleration of electrons in the field of ions, and (iii) the electron impact excitation of not fully ionized impurity atoms in the plasma.Ad (i): The acceleration by the Lorentz force causes the electrons and ions to gyrate around the magnetic field lines, resulting in what is called ion cyclotron emission and electron cyclotron emission, ICE and ECE, respectively. The frequency range is determined by the local confining B-field and the aspect ratio of the device. In modern fusion experiments, the ICE lies within 10-100 MHz, while the ECE lies within 50-500 GHz. Only ECE has gained diagnostic significance. Ad (ii): The continuous emission connected with electron ion collisions is called bremsstrahlung. If the electrons and ions are free before and after the encounter, the emission is called free-free radiation. If the electrons are captured by ions into a bound state, the emission connected with the process is called recombination radiation, or free-bound radiation. Both terms, free-free and free-bound radiations, are synonymously used with the term bremsstrahlung. Bremsstrahlung covers the spectral range from the microwave to the soft X-ray region. Most important diagnostic applications are in the visible and the soft X-ray regions. Ad (iii): If impurities are present in the plasma, they can be ionized by electron impact. The degree of ionization depends on the local electron temperature. While atoms with lower atomic numbers in low ionization states can be found at the low-temperature plasma edge, in the hot-plasma center, only ions with high nuclear charge can exist in high, but not fully ionized states. Spectral lines characteristic for the ion species and the ionization state are emitted after electron impact excitation. The spectral range extends typically from the optical into the X-ray regime. Spectroscopy of line emission from the plasma is the classical plasma diagnostic method in the optical, UV, VUV, and X-ray regions. It allows for the determination of a number of important plasma parameters; in particular, it allows for the quantification of the plasma impurity content. While the ion species and the ionization state of the impurities are uniquely determined by the wavelength of the emitted spectral line,

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Production and Electron Heating of Over‐Dense Plasmas by 2.45 GHz Electron Bernstein Waves on CHS

Ikeda

Igami

Toi

et al. 2010

Contrib. Plasma Phys.

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Key words Electron Bernstein wave, over-dense plasma, compact helical system. Production and heating of over-dense plasmas by 2.45 GHz microwave system under very low field condition was performed and demonstrated on CHS. In this experiment, microwave systems were arranged to aim at taking place mode conversion of launched electron cyclotron wave effectively into electron Bernstein wave (EBW). The power deposition profiles in produced over-dense plasmas were measured directly by using power modulation technique at various magnetic configurations. The power deposition took place dominantly in overdense region. To clarify wave trajectories, power absorption mechanism and mode conversion, a numerical analysis by a ray-tracing method was performed. Calculated ray-trajectories accessed to the region where the experimentally obtained deposition profile has a peak.

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Excitation, propagation, and damping of electron Bernstein waves in tokamaks

Cited by 141 publications

References 15 publications

On electron Bernstein waves in spherical tori

On electron Bernstein waves in spherical tori

Passive Diagnostics

Production and Electron Heating of Over‐Dense Plasmas by 2.45 GHz Electron Bernstein Waves on CHS

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