Anomalous Transport in Plasma
Theoretical and Numerical Analysis of Anomalous Transport in a Field - Reversed Configuration
Tech Area / Field
- FUS-PLA/Plasma Physics/Fusion
8 Project completed
Senior Project Manager
Bugaev D V
MGTU (Moscow State Technical University) / Research Institute of Power Ingineering, Russia, Moscow
- VNIIEF, Russia, N. Novgorod reg., Sarov
- University of Washington / Redmond Plasma Physical Laboratory, USA, WA, Seattle\nLos-Alamos National Laboratory, USA, NM, Los-Alamos\nOsaka University / Graduate School of Engineering, Japan, Osaka\nUniversity of Wisconsin-Madison / Fusion Technology Institute, USA, WI, Madison
Project summaryA Field-Reversed Configuration is one of the most attractive and promising magnetic confinement system. The comparison of the principal features of FRC with the same of the tokamaks has considerable utility.
In contrast tokamaks, FRC has no toroidal magnetic field. This allows to obtain high beta values and consequently higher fusion power output. The last parameter in tokamaks will be 10 times less than in fission reactors, while FRC may exceed this limit.
Moreover, FRC has linear cylindrical geometry with natural pertor thus providing intrinsic engineering advantages. At least, it seems possible to build relatively compact Test Fusion Reactor on the base of FRC.
So, the most promising features of FRC are as follows: a) small size; b) relatively low cost; c) the possibility of high beta operation and high fusion specific power output which would be comparable with fission reactor; d) the possibility of modification of plasma volume in order to obtain better plasma parameters.
Due to these features FRC are under intensive study nowadays. The most important results are presented in [M. Tuszewski, Nucl. Fusion 28, 2033 (1988)].
In 1996 the International Research Program has been developed - FRC-2001. BMSTU group is a co-author of this program [FRC 2001, Fusion Technology 30, 116 (1996)].
The possibility of using of FRC as a low-radioactive D-3He reactor is widely discussed [И.Н.Головин //Препринт ИАЭ № 4885/8.-М.:Цнииатоминформ.-1989].
The present plasma parameters achieved in experiment are [A.L.Hoffman, Reactor prospects and present status of FRC //Trans. of Fusion Technology.-1995.-V.27.-P.91-96]: - density 5 ґ 1013 - 5 ґ 1015 cm-3; - temperature 3 keV (ions) и 500 eV (electrons); - beta 0.75 - 0.95.
One of the main problems in FRC physics is large value of diffusion coefficient (of order of 10 M2/s). This is the result of anomalous transport, which is not well known.
Moreover, data of the different groups of researches are inconsistent with one another. In [N.Krall // Phys.Fluids.-1989.-V.B1.-P.1811-1817], the main attention was paid to low-hybrid and drift dissipate low frequency instabilities as a source of anomalous transport. At the same time authors [Okada S., Ueki S., et al. // Trans. of Fusion Technology.-1995.-V.27.-P.341-344] on the base of FIX experiment have none of that instabilities in FRC plasma. Experimental spectra of low frequency magnetic field fluctuations are not explained yet. Moreover, experimental data [L.Steinhauer FRC DATA DIGEST, Int.Workshop on FRC, Nagoya, 1996] handling proves the presence of different transport mechanisms on the various series of experimental installations.
The main difficulties of FRC plasma microinstabiliies investigations are connected with next features: - strongly inhomogeneous magnetic field and plasma density (on plasma edge (b<<1, inside plasma core (b>>1); - dependence of plasma density on magnetic field distribution.
So, now, we have no correct picture of microinstabilities nature in FRC. That is why it is necessary to analyze the possible mechanisms of microinstabilities driven and compare the results of such analysis with experimental data in order to build correct theory of anomalous transport and find the way of suppression of anomalous fluxes as it has been done on open systems [T.Tamano //Trans. of Fusion Technology.-1995.-V.27.-P. 111-116] and tokamaks [JT-60 Team]. It is the way to reach the main purpose - obtain reactor FRC plasma parameters.
From the above, we postulate the necessity of the following directions of investigation:
- analysis of the different types of particle/energy transport for various plasma conditions;
- development of computer codes of equilibrium and turbulent FRC plasma simulation.
Before, practically all estimations have been done analytically. In this project we want to use more computer simulations.
Basic expected results of work are the answer to a problem on the mechanism of an anomalous transport in FRC. It has a large scientific value. The main results are following: 1) Method and results of calculations self-consistent magnetic field, current density and plasma density distribution. 2) Results of calculation of particles dynamics and corresponding estimates of direct particles losses through little part of separatrix surface contiguous to X-point. 3) Calculations of magnetic reconnection and estimations of plasma losses connected with one. 4) Linear analysis of different types of microinstabilities. 5) Nonlinear analysis of microinstabilities and estimations of anomalous transport processes.
The solution of these problems makes necessary the developing of complex models, including the calculation of magnetic fields, the inclusion of nonlinear plasma-waves interaction and considering wide spectra of plasma instabilities.
Research group of Power Engineering Institute of BMSTU has wide international relations with the following groups:
1) National Institute for Fusion Science - Nagoya, Japan;
2) Niigata University - Niigata, Japan;
3) University of Wisconsin- Madison, USA;
4) University of Washington - Sietle, USA.
Program of investigations is coordinated with the American side on behalf of Prof. L. Steinhauer (University of Washington, Siettle, USA), which yield consent on the participation in performing a given project.
The project is a part of fundamental investigations in the field of fusion energy, thus integrates directions of energy production and environmental, declared by ISTC.
The available theoretical and program backlog allows calculating for successful realization of the marked program of researches in cooperation Power Engineering Institute, Russian Federal Nuclear Center (Arzamas-16) and foreign collaborators. Principal direction of cooperation - share realization of numerical experiments and share development of a code of a particles method.