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

Part of: PLA 17th European Fusion Theory Conference Focus on Fusion

Published online by Cambridge University Press:  18 December 2018

S. I. Valvis ,
A. K. Ram ,
K. Hizanidis ,
P. Papagiannis ,
A. Papadopoulos ,
A. Zisis ,
I. G. Tigelis  and
E. Glytsis
S. I. Valvis*
Affiliation:
School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens 15780, Greece
A. K. Ram
Affiliation:
Plasma Science and Fusion Center, Massachusetts Institute of Technology, 175 Albany Street, Cambridge, MA 02139, USA
K. Hizanidis
Affiliation:
School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens 15780, Greece
P. Papagiannis
Affiliation:
School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens 15780, Greece
A. Papadopoulos
Affiliation:
School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens 15780, Greece
A. Zisis
Affiliation:
Faculty of Physics, National and Kapodistrian University of Athens, University Campus, Zografou, Athens 15784, Greece
I. G. Tigelis
Affiliation:
Faculty of Physics, National and Kapodistrian University of Athens, University Campus, Zografou, Athens 15784, Greece
E. Glytsis
Affiliation:
School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens 15780, Greece
*
†Email address for correspondence: [email protected]
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Abstract

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 $f_{0}=170~\text{GHz}$) 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.

Keywords

fusion plasmaplasma waves
Type
Research Article
Information
Journal of Plasma Physics , Volume 84 , Issue 6 , December 2018 , 745840604
Copyright
© Cambridge University Press 2018 

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References

Abramowitz, M. & Stegun, I. A. 1972 Handbook of Mathematical Functions. Dover.Google Scholar
Griffiths, D. J. 1999 Introduction to Electrodynamics, 3rd edn. Pearson.Google Scholar
Grulke, O., Terry, J. L., Cziegler, I., Labombard, B. & Garcia, O. E. 2014 Experimental investigation of the parallel structure of fluctuations in the scrape-off layer of Alcator C-Mod. Nucl. Fusion 54, 043012.Google Scholar
Grulke, O., Terry, J. L., Labombard, B. & Zweben, S. J. 2006 Radially propagating fluctuation structures in the scrape-off layer of Alcator C-Mod. Phys. Plasmas 13, 012306.Google Scholar
Hizanidis, K., Ram, A. K., Kominis, Y. & Tsironis, C. 2010 Fokker–Planck description of the scattering of radio frequency waves at the plasma edges. Phys. Plasmas 17, 022505.Google Scholar
Ioannidis, Z. C., Ram, A. K., Hizanidis, K. & Tigelis, I. G. 2017 Computational studies on scattering of radio frequency waves by density filaments in fusion plasmas. Phys. Plasmas 24, 102115.Google Scholar
Krasheninnikov, S. I. 2001 On scrape off layer plasma transport. Phys. Lett. A 283, 368–370.Google Scholar
Myra, J. R., D’ Ippolito, D. A., Stotler, D. P., Zweben, S. J., Leblanc, B. P., Menard, J. E., Maqueda, R. J. & Boedo, J. 2006 Blob birth and transport in the tokamak edge plasma: analysis of imaging data. Phys. Plasmas 13, 092509.Google Scholar
Myra, J. R., Russell, D. A. & D’Ippolito, D. A. 2006 Collisionality and magnetic geometry effects on tokamak edge turbulent transport. I. A two-region model with application to blobs. Phys. Plasmas 13, 112502.Google Scholar
Pigarov, A. Yu., Krasheninnikov, S. I. & Rognlien, T. D. 2012 Time-dependent 2-D modeling of edge plasma transport with high intermittency due to blobs. Phys. Plasmas 19, 072516.Google Scholar
Prisiazhniuk, D. et al. 2017 Magnetic field pitch angle and perpendicular velocity measurements from multi-point time-delay estimation of poloidal correlation reflectometry. Plasma Phys. Control. Fusion 59, 025013.Google Scholar
Ram, A. K. & Hizanidis, K. 2013 Scattering of electromagnetic waves by a plasma sphere embedded in a magnetized plasma. Radiati. Effects Defects Solids 168, 759–775.Google Scholar
Ram, A. K. & Hizanidis, K. 2016 Scattering of radio frequency waves by cylindrical density filaments in tokamak plasmas. Phys. Plasmas 23, 022504.Google Scholar
Ram, A. K., Hizanidis, K. & Kominis, Y. 2013 Scattering of radio frequency waves by blobs in tokamak plasmas. Phys. Plasmas 20, 056110.Google Scholar
Stix, T. H. 1992 Waves in Plasmas. American Institute of Physics.Google Scholar
Stratton, J. A. 1941 Electromagnetic Theory. McGraw Hill.Google Scholar
Taylor, G., Efthimion, P. C., Leblanc, B. P., Carter, M. D., Caughman, J. B., Wilgen, J. B., Preinhaelter, J., Harvey, R. W. & Sabbagh, S. A. 2005 Efficient coupling of thermal electron Bernstein waves to the ordinary electromagnetic mode on the national spherical torus experiment. Phys. Plasmas 12, 052511.Google Scholar
Zweben, S. J., Boedo, J. A., Grulke, O., Hidalgo, C., Labombard, B., Maqueda, R. J., Scarin, P. & Terry, J. L. 2007 Edge turbulence measurements in toroidal fusion devices. Plasma Phys. Control. Fusion 49, S1–S23.Google Scholar