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Title: Scattering of radio frequency waves by cylindrical filaments with general orientation relative to the magnetic field

Journal Article · · Journal of Plasma Physics
 [1];  [2];  [1];  [1];  [1];  [3];  [3];  [1]
  1. National Technical University of Athens (Greece)
  2. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States)
  3. National and Kapodistrian University of Athens (Greece)
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We report Radio frequency (RF) waves are routinely used in tokamak fusion plasmas for plasma heating, current control, as well as in diagnostics. These waves are excited by antenna structures placed near the tokamak’s wall and they have to propagate through a turbulent layer known as the scrape-off layer, before reaching the core plasma (which is their target). This layer exhibits coherent density fluctuations in the form of filaments and blobs. The scattering processes of RF plane waves by a single filament is studied with the assumption that the filament has a cylindrical shape and infinite length. Furthermore, besides the major toroidal component of the externally imposed magnetic field, there is also a small poloidal magnetic field component. Considering also that the cylindrical filament’s axis is not necessarily aligned with the toroidal direction, the total magnetic field is in general neither aligned with the axis of the cylinder nor with the toroidal direction. The investigation concerns the case of electron cyclotron (EC) waves (of frequency $$f_0$$ = 170 GHz)for tokamak applications. The study covers a variety of density contrasts between the filament and the ambient plasma, different magnetic field inclinations with respect to the cylinder axis (for the same magnitude of magnetic induction B = 4.5T and a wide range of filament radii.

Research Organization:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); Euratom research and training programme
Grant/Contract Number:
FC02-01ER54648; FG02-91ER54109; FG02-99ER54525; 633053
OSTI ID:
1609002
Report Number(s):
PSFC/JA-18-54; PII: S0022377818001083
Journal Information:
Journal of Plasma Physics, Vol. 84, Issue 6; ISSN 0022-3778
Publisher:
Cambridge University PressCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

References (14)

Radially propagating fluctuation structures in the scrape-off layer of Alcator C-Mod journal January 2006
Computational studies on scattering of radio frequency waves by density filaments in fusion plasmas journal October 2017
Experimental investigation of the parallel structure of fluctuations in the scrape-off layer of Alcator C-Mod journal March 2014
On scrape off layer plasma transport journal May 2001
Blob birth and transport in the tokamak edge plasma: Analysis of imaging data journal September 2006
Scattering of radio frequency waves by blobs in tokamak plasmas journal May 2013
Scattering of electromagnetic waves by a plasma sphere embedded in a magnetized plasma journal October 2013
Time-dependent 2-D modeling of edge plasma transport with high intermittency due to blobs journal July 2012
Magnetic field pitch angle and perpendicular velocity measurements from multi-point time-delay estimation of poloidal correlation reflectometry journal January 2017
Edge turbulence measurements in toroidal fusion devices journal June 2007
Efficient coupling of thermal electron Bernstein waves to the ordinary electromagnetic mode on the National Spherical Torus Experiment journal May 2005
Scattering of radio frequency waves by cylindrical density filaments in tokamak plasmas journal February 2016
Collisionality and magnetic geometry effects on tokamak edge turbulent transport. I. A two-region model with application to blobs journal November 2006
Fokker–Planck description of the scattering of radio frequency waves at the plasma edge journal February 2010

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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plasma waves