Cyclotron radiation as a diagnostic tool for tokamak plasmas

Celata, C.M.; Boyd, D. A.

doi:10.1088/0029-5515/17/4/009

Cited by 75 publications

(45 citation statements)

References 2 publications

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“…The first measurements of ECE were made in the early 1970s by Costley et al 1 . The potential for using the ECE spectrum to diagnose plasmas was suggested by Engelmann and Curatolo 2 and Celata and Boyd 3 . A review of ECE physics and the diagnostic potential of ECE can be found in Bornatici et al 4 .…”

Section: Introductionmentioning

confidence: 99%

Electron Bernstein wave electron temperature profile diagnostic

Taylor¹,

Efthimion²,

Jones³

et al. 2000

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Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either "overdense", operating at high density relative to the magnetic field (e.g. w pe >> W ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (t >2). Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large k perp . This paper reports on measurements of EBW emission on the CDX-U spherical torus, where B o ~ 2 kG, 10 13 cm -3 and T e » 10 -200 eV. Results are presented for electromagnetic measurements of EBW emission, mode-converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multipoint Thomson scattering diagnostic. Depending on the plasma conditions, the modeconverted EBW radiation temperature was found to be £ T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where w pe >> W ce .

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Section: Introductionmentioning

confidence: 99%

Electron Bernstein wave electron temperature profile diagnostic

Taylor¹,

Efthimion²,

Jones³

et al. 2000

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“…20,21 The first ECE measurements from a tokamak were performed on the CLEO device using a Michelson interferometer and InSb detector 22 with early theoretical studies providing a sound foundation for measurement and interpretation. 23,24 This was rapidly followed by measurements on devices throughout the world. Today, this is a routine technique for obtaining electron temperature profiles using a variety of instrument configurations.…”

Section: I~v! ϭ Vmentioning

confidence: 99%

Chapter 3: Microwave Diagnostics

Luhmann

Bindslev

Park

et al. 2008

Fusion Science and Technology

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“…Thus, ECE detection from the high-field side ͑HFS͒ of the resonance is a sensitive diagnostic of high-v Ќ electrons whereas oblique LFS detection targets preferentially high-v ʈ electrons. 71,72 The photon statistics of cyclotron emission being generally far better than those of HXR bremsstrahlung, exploiting ECE for diagnosing suprathermal electrons offers in principle a way to achieve superior time resolution. On the other hand, ECE suffers from the significant complication that the energy and the spatial location of the emitting electrons cannot be determined independently in general.…”

Section: Electron-cyclotron Radiationmentioning

confidence: 99%

Diagnostic techniques for measuring suprathermal electron dynamics in plasmas (invited)

Coda

2008

Review of Scientific Instruments

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Plasmas, both in the laboratory and in space, are often not in thermodynamic equilibrium, and the plasma electron distribution function is accordingly non-Maxwellian. Suprathermal electron tails can be generated by external drives, such as rf waves and electric fields, or internal ones, such as instabilities and magnetic reconnection. The variety and importance of the phenomena in which suprathermal electrons play a significant role explains an enduring interest in diagnostic techniques to investigate their properties and dynamics. X-ray bremsstrahlung emission has been studied in hot magnetized plasmas for well over two decades, flanked progressively by electron-cyclotron emission in geometries favoring the high-energy end of the distribution function ͑high-field-side, vertical, oblique emission͒, by electron-cyclotron absorption, by spectroscopic techniques, and at lower temperatures, by Langmuir probes and electrostatic analyzers. Continuous progress in detector technology and in measurement and analysis techniques, increasingly sophisticated layouts ͑multichannel and tomographic systems, imaging geometries͒, and highly controlled suprathermal generation methods ͑e.g., perturbative rf modulation͒ have all been brought to bear in recent years on an increasingly detailed, although far from complete, understanding of suprathermal electron dynamics.

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Cyclotron radiation as a diagnostic tool for tokamak plasmas

Cited by 75 publications

References 2 publications

Electron Bernstein wave electron temperature profile diagnostic

Electron Bernstein wave electron temperature profile diagnostic

Chapter 3: Microwave Diagnostics

Diagnostic techniques for measuring suprathermal electron dynamics in plasmas (invited)

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