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September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Fusion Science and Technology
Latest News
Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
R. Balescu
Fusion Science and Technology | Volume 33 | Number 2 | March 1998 | Pages 192-206
Transport in Tokamaks | doi.org/10.13182/FST98-A11947010
Articles are hosted by Taylor and Francis Online.
The methods of modern theory of stochastic processes appear to provide a useful tool for transport theory in magnetized plasmas. The Langevin equation formalism provides important, but limited information about diffusive processes. A quite promising new approach to modelling complex situations, such as transport in incompletely destroyed magnetic surfaces, is provided by the theory of Continuous Time Random Walks (CTRW), which is presented in some detail. A test problem is discussed in detail: transport of particles in a fluctuating magnetic field, in the limit of infinite perpendicular correlation length. The well-known subdiffusive behavior of the Mean Square Displacement (MSD), proportional to t1/2, is recovered by a CTRW, but the complete density profile is only recovered under some additional conditions. The quasilinear approximation of the kinetic equation has the form of a non-markovian diffusion equation and can thus be generated by a CTRW. Finally, a new iterative map, called “tokamap” is presented and its relation to transport and CTRW is displayed.
