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TJ-II:Reflectometry: Difference between revisions
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[[File:DRscheme.jpg|200px|thumb|right|Schematic drawing of the Doppler Reflectometer System of TJ-II.]] | [[File:DRscheme.jpg|200px|thumb|right|Schematic drawing of the Doppler Reflectometer System of TJ-II.]] | ||
Since February 2009, the frequency hopping system is in operation in oblique incidence (''Doppler'' reflectometry, [[TJ-II:Sectors|sector]] C6) <ref>[http://link.aip.org/link/?RSINAK/80/073502/1 T. Happel, T. Estrada, E. Blanco, V. Tribaldos, A. Cappa, and A. Bustos, Rev. Sci. Instrum. '''80''' (2009) 073502]</ref>, measuring plasma density fluctuation velocities and their wave number spectra. The system is able to measure in a radial range of about ρ = 0.6 - 0.9 (ρ = r/a is the effective plasma radius) and the perpendicular wavenumber can be selected between 3 and 15 cm<sup>-1</sup>. | Since February 2009, the frequency hopping system is in operation in oblique incidence (''Doppler'' reflectometry, [[TJ-II:Sectors|sector]] C6) <ref>[http://link.aip.org/link/?RSINAK/80/073502/1 T. Happel, T. Estrada, E. Blanco, V. Tribaldos, A. Cappa, and A. Bustos, Rev. Sci. Instrum. '''80''' (2009) 073502]</ref>, measuring plasma density fluctuation velocities and their wave number spectra. The system is able to measure in a radial range of about ρ = 0.6 - 0.9 (ρ = r/a is the effective plasma radius) and the perpendicular wavenumber can be selected between 3 and 15 cm<sup>-1</sup>. | ||
The system consists of a circular choked-corrugated antenna | |||
<ref>[http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=1696015 J. Teniente, R. Gonzalo, and C. del-Rio, IEEE Antennas Wireless Propag. Lett. '''5''' (2006) 380]</ref> | |||
(fabricated by the ''Antenna Group of the Public University of Navarra, Spain'') which emits a microwave beam with a gaussian electric field distribution. The beam is reflected by a steerable ellipsoidal mirror to the plasma. The mirror serves for two purposes: 1) focus the microwave beam to the region where backscattering takes place and 2) change the angle of incidence between beam and plasma, giving the possibility to select the turbulence scale to be measured. | |||
==References== | ==References== | ||
<references /> | <references /> | ||