TITLE

A monitor of chord-averaged plasma density

AUTHOR(S)
Petrov, V.; Petrov, A.; Malyshev, A.; Markov, V.; Babarykin, A.
PUB. DATE
March 2006
SOURCE
Instruments & Experimental Techniques;Mar2006, Vol. 49 Issue 2, p238
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A single-channel two-frequency chord-averaged density monitor for measuring the plasma density in tokamaks is described. The operating principle of the monitor is based on measuring the phase shift between two microwave signals at close frequencies transmitted through plasma along one and the same chord. At an appropriately chosen difference between these frequencies, the measured phase difference is <2π in the entire range of measured densities, thereby ensuring measurements without fringe jumps. The advantage of this method for measuring the delay time compared to the pulsed method consists in an increased sensitivity of measurements owing to the possibility of filtering signals at fairly high intermediate frequency (∼0.5–1 GHz). It is additionally possible to adjust the dynamic range of density measurements by selecting (optimizing) the frequency difference. The schematic diagram and the main performance characteristics of the monitor are presented. The results from laboratory tests of the monitor and those obtained with it on the T-11M facility are presented. The range of density measurements is 0.7 × 1012–0.7 × 1014 cm-3, the measurement accuracy is no worse than 1%, and the temporal resolution reaches 30 ns.
ACCESSION #
20457282

 

Related Articles

  • Second stable regime of internal kink modes excited by barely passing energetic ions in tokamak plasmas. He, H. D.; Dong, J. Q.; Fu, G. Y.; Zheng, G. Y.; Sheng, Z. M.; Long, Y. X.; He, Z. X.; Jiang, H. B.; Shen, Y.; Wang, L. F. // Physics of Plasmas;Aug2010, Vol. 17 Issue 8, p082512 

    The internal kink (fishbone) modes, driven by barely passing energetic ions (EIs), are numerically studied with the spatial distribution of the EIs taking into account. It is found that the modes with frequencies comparable to the toroidal precession frequencies are excited by resonant...

  • Temperature and density characteristics of the Helicity Injected Torus-II spherical tokamak indicating closed flux sustainment using coaxial helicity injection. Hamp, W. T.; Jarboe, T. R.; Nelson, B. A.; O'Neill, R. G.; Raman, R.; Redd, A. J.; Stewart, B. T.; Mueller, D. // Physics of Plasmas;Aug2008, Vol. 15 Issue 8, p082501 

    The electron temperature and density profiles of plasmas in the Helicity Injected Torus [HIT-II: T. R. Jarboe et al., Phys. Plasmas 5, 1807 (1998)] experiment are measured by multipoint Thomson scattering (MPTS). The HIT-II device is a small low-aspect-ratio tokamak (major radius 0.3 m, minor...

  • ELMy Studies in ITER Relevant Regimes in ASDEX Upgrade Broadband FM-CW Reflectometry Techniques. Manso, M.; Silva, A.; Varela, P.; Borba, D.; Lang, P.; Cupido, L.; Nunes, I.; Conway, G. // AIP Conference Proceedings;2006, Vol. 875 Issue 1, p363 

    We present a study performed in ASDEX Upgrade H mode regime based on results from the broadband FM-CW reflectometry diagnostic, equipped with the unique capability of measuring the plasma density profile both at the low and high field sides of the tokamak. The plasma edge dynamics due to fast...

  • Structure of Global Tokamak Scalings. Dnestrovskij, Yu. N. // Plasma Physics Reports;Feb2002, Vol. 28 Issue 2, p166 

    In empirical tokamak scalings, not all of the standard engineering parameters are independent. Thus, the larger the tokamak, the higher the required plasma current and input power. Also, by using higher magnetic fields, it is possible to raise the plasma density. Instead of the plasma density,...

  • Sawtooth studies with q-profile measurement on TFTR(abstract)[sup a]. Levinton, F.M.; Batha, S.H.; Yamada, M.; Zakharov, L.; Zarntorff, M.C. // Review of Scientific Instruments;Jan1995, Vol. 66 Issue 1, p372 

    Measures the q profile for plasma equilibrium and theories of MHD instabilities in a Tokamak Fusion Test Reactor (TFTR). Measurement of diagnostic and accurate profiles.

  • High-Q plasmas in the TFTR tokamak. Jassby, D. L.; Barnes, C. W.; Bell, M. G.; Bitter, M.; Boivin, R.; Bretz, N. L.; Budny, R. V.; Bush, C. E.; Dylla, H. F.; Efthimion, P. C.; Fredrickson, E. D.; Hawryluk, R. J.; Hill, K. W.; Hosea, J.; Hsuan, H.; Janos, A. C.; Jobes, F. C.; Johnson, D. W.; Johnson, L. C. // Physics of Fluids B: Plasma Physics;Aug91, Vol. 3 Issue 8, p2308 

    In the Tokamak Fusion Test Reactor (TFTR) [Plasma Phys. Controlled Fusion 26, 11 (1984) ], the highest neutron source strength S[sub n] and D-D fusion power gain Q[sub DD] are realized in the neutral-beam-fueled and heated "supershot" regime that occurs after extensive wall conditioning to...

  • Performance of the Tokamak Fusion Test Reactor bolometers. Schivell, J. // Review of Scientific Instruments;May85, Vol. 56 Issue 5, p972 

    For the past year we have been making use of a horizontally viewing 19-channel array and a bolometer which views a narrow cross-sectional slice of the plasma. More recently, we have also obtained results from a second, vertically viewing array. Software has been developed to translate the data...

  • Injection of a High-Density Plasma into the Globus-M Spherical Tokamak. Abramova, K. B.; Voronin, A. V.; Gusev, V. K.; Mukhin, E. E.; Petrov, Yu. V.; Sakharov, N. V.; Chernyshev, F. V. // Plasma Physics Reports;Sep2005, Vol. 31 Issue 9, p721 

    A new type of plasma source with titanium hydride granules used as a hydrogen accumulator was employed to inject a dense, highly ionized plasma jet into the Globus-M spherical tokamak. The experiments have shown that the jet penetrates through the tokamak magnetic field and increases the plasma...

  • Detachment and divertor temperature and density redistribution. Stacey, Weston M. // Physics of Plasmas;Feb2001, Vol. 8 Issue 2, p525 

    A theoretical model is developed for large scale-length, one-dimensional thermal instabilities along the field lines in tokamak divertors. Calculated growth rates predict a divertor thermal instability under the conditions (low-plasma temperature and density and high-neutral densities at the...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics