Acoustic mode driven by fast electrons in TJ-II Electron Cyclotron Resonance plasmas

Author： Sun B. J.   Ochando M. A.   López-Bruna D.  

Publisher： Edp Sciences

E-ISSN： 1286-4854|115|3|35001-35001

ISSN： 0295-5075

Source： EPL (EUROPHYSICS LETTERS), Vol.115, Iss.3, 2016-09, pp. : 35001-35001

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Intense harmonic oscillations in radiation signals $(\delta I/I\sim 5{\%})$ are commonly observed during Electron Cyclotron Resonance (ECR) heating in TJ-II stellarator plasmas at low line-averaged electron density, $0.15 < \bar{n}_e < 0.6 \times10^{19} \ \text{m}^{-3}$ . The frequency agrees with acoustic modes. The poloidal modal structure is compatible with Geodesic Acoustic Modes (GAM) but an $n \neq 0$ toroidal structure is detected. The modes are found in the proximity of low-order rationals of the rotational transform (${\lower3pt\hbox{$\mathchar'26$}\mkern-7mu\iota} = 1/q = 8/5$ in this work) and are excited by fast-electron populations, but they disappear at the onset of ${\lower3pt\hbox{$\mathchar'26$}\mkern-7mu\iota}$ -islands rotation.

Related content

Transport analysis in an electron cyclotron heating power scan of TJ-II plasmas

By Team The TJ-II   Tallents S   López-Bruna D   Velasco J L   Ochando M A     Vargas V I   Martinell J J   Tafalla D   Fontdecaba J M   Herranz J   Blanco E   Tabarés F L   Estrada T   Pastor I  

Plasma Physics and Controlled Fusion, Vol. 56, Iss. 7, 2014-07 ,pp. : 75024-75033 (10)

IOP Publishing

Access to resources Recommend Favorite

Tracking magnetic resonances in the effective electron heat diffusivity of ECH plasmas of the TJ-II Heliac

By  

EPL (EUROPHYSICS LETTERS), Vol. 82, Iss. 6, 2008-06 ,pp. : 65002-65002 (1)

Edp Sciences

Access to resources Recommend Favorite

Edge localised mode-like instability driven plasma edge burst study in the TJ-II Stellarator

By Team the TJ-II   Team the TJ-II  

Plasma Physics and Controlled Fusion, Vol. 57, Iss. 7, 2015-07 ,pp. : 75001-75013 (13)

IOP Publishing

Access to resources Recommend Favorite

Transport in threshold plasmas for a confinement transition in the TJ-II stellarator

By Team the TJ-II   López-Bruna D   Velasco J L   Ochando M   Guasp J   López-Fraguas A   van Milligen B P   Ascasíbar E   Liniers M   Estrada T   Fontdecaba J M   Pastor I   Tafalla D   Medina F   Eliseev L   Melnikov A   Perfilov S   Herranz J   Zurro B   McCarthy K J   Tabarés F  

Plasma Physics and Controlled Fusion, Vol. 55, Iss. 1, 2013-01 ,pp. : 15001-15011 (11)

IOP Publishing

Access to resources Recommend Favorite

Are magnetic resonances practical transport controllers in fusion plasmas? The TJ-II experience

By  

Journal of Physics: Conference Series , Vol. 591, Iss. 1, 2015-03 ,pp. : 110-118 (9)

IOP Publishing

Access to resources Recommend Favorite