Ion temperature and beam-driven plasma waves from collective scattering of gyrotron radiation in W7-AS

Суворов, Е. В.; Erckmann, V.; Holzhauer, E.; Kasparek, W.; Dryagin, Yu. A.; Fil'chenkov, S. E.; Fraiman, A. A.; Geist, T.; Kick, M.; Kukin, L. M.; Костров, А. В.; Lubyako, L. V.; Shtanyuk, A. M.; Skalyga, N. K.; Smolyakova, O. B.

doi:10.1088/0741-3335/37/11/002

Cited by 63 publications

(57 citation statements)

References 7 publications

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“…The advantage of using gyrotrons is the longer pulse periods together with the longer wavelength which reduces the restrictions on the scattering geometry. In 1995, a 140 GHz gyrotron (λ ∼ 2.1 mm) was used to obtain the ion temperature in the stellarator W7-AS [33], and a year later ion temperature measurements were reported from JET [34] also using a 140 GHz gyrotron.…”

Section: Bulk Ion Cts Measurementsmentioning

confidence: 99%

Recent development of collective Thomson scattering for magnetically confined fusion plasmas

et al. 2016

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Abstract. Here we review recent experimental development within the field of collective Thomson scattering with focus on the progress made on the devices TEXTOR and ASDEX Upgrade. We discuss recently discovered possibilities and limitations of the diagnostic technique. Diagnostic applications with respect to ion measurements are demonstrated. Examples include measurements of the ion temperature, energetic ion distribution function, and the ion composition.

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Section: Bulk Ion Cts Measurementsmentioning

confidence: 99%

Recent development of collective Thomson scattering for magnetically confined fusion plasmas

et al. 2016

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“…At lower frequency shifts, in the bulk ion region of the spectrum, CTS measurements provide information about thermal ion populations including properties such as the ion temperature and drift a) mspe@fysik.dtu.dk velocity (i.e. plasma rotation) [20][21][22][23][24][25][26][27][28][29][30] . For certain scattering geometries and plasma conditions, the bulk ion region of CTS spectra can also contain signatures of the ion cyclotron motion and of plasma waves such as the ion acoustic wave, ion Bernstein waves and fast magnetosonic waves.…”

mentioning

confidence: 99%

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Stejner

Nielsen

Jacobsen

et al. 2014

Review of Scientific Instruments

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Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity and plasma composition.

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“…However, as T e and T i increase gradually with the decrease of n e and fast ions with parallel velocity are produced by co-and counter NBs, the peak frequencies shift to downward and merge to the bulk ion region. This phenomenon is considered not to be a change of the distribution function of fast ions related to 40 keV NB, but to be an excitation of a NB driven turbulence such as lower hybrid waves, which are pointed out at W7-AS [11]. The frequencies of perpendicular fast ion driven waves and theoretical lower hybrid waves are plotted as a function of the electron density in Fig.…”

Section: Time Evolution Of Bulk and Fast Ions By Cts Spectrummentioning

confidence: 99%

“…5. The lower hybrid wave is calculated by the relation as the cold magnetized plasma approximation [11],…”

Section: Time Evolution Of Bulk and Fast Ions By Cts Spectrummentioning

confidence: 99%

Development of Collective Thomson Scattering Diagnostic for Bulk and Fast Ions in the Large Helical Device

Nishiura

Kubo

Tanaka

et al. 2011

Plasma and Fusion Research

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The collective Thomson scattering (CTS) technique has been utilized with the backscattering configuration to diagnose the bulk and fast ions in the Large Helical Device (LHD). The spectrogram of the scattered radiation presents the transient phenomena related to fast ion slowing down in auxiliary neutral beam heated plasmas. This is obtained by the broad band receiver resolving with 32 channels, while the probing beam from 77 GHz gyrotron is modulated with 50 Hz and is injected into plasmas. In the same shot, especially in low temperature plasma (T e , T i < 1 keV), a wave excitation is also observed in a narrow frequency band. The peaks in the CTS spectrum exist between 0.5 and 1.0 GHz and are observed in both frequency sides asymmetry. For the forthcoming experiments, the feasibility of CTS diagnostics at a new port location is assessed to extend the diagnostic capability for measuring the ion velocity components. Expected spectra for scattered radiation are the same signal level as the present location from a numerical calculation.

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Ion temperature and beam-driven plasma waves from collective scattering of gyrotron radiation in W7-AS

Cited by 63 publications

References 7 publications

Recent development of collective Thomson scattering for magnetically confined fusion plasmas

Recent development of collective Thomson scattering for magnetically confined fusion plasmas

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Development of Collective Thomson Scattering Diagnostic for Bulk and Fast Ions in the Large Helical Device

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