Driven Current Tokamak (DCT) Scoping Study

Design Features of Tokamak Power Reactors with Rf-driven Steady State Current

Observation of self-generated flows in tokamak plasmas with lower-hybrid-driven current.

In Alcator C-Mod discharges lower hybrid waves have been shown to induce a countercurrent change in toroidal rotation of up to 60 km/s in the central region of the plasma (r/a approximately <0.4). This modification of the toroidal rotation profile develops on a time scale comparable to the current redistribution time (approximately 100 ms) but longer than the energy and momentum confinement tim...

Experimental observations of driven and intrinsic rotation in tokamak plasmas

Experimental observations of driven and intrinsic rotation in tokamak plasmas are reviewed. For momentum sources, there is direct drive from neutral beam injection, lower hybrid and ion cyclotron range of frequencies waves (including mode conversion flow drive), as well as indirect j B × forces from fast ion and electron orbit shifts, and toroidal magnetic field ripple loss. Counteracting rotat...

Characteristics of Rf-driven Steady State Tokamak Power Reactors

The use of lower hybrid waves for current drive in steady state tokamak power reactors is studied. Constraints imposed by rf wave propagation are considered in detail. The effect of decoupling of electron and ion temperatures is studied and is found to enhance significantly the ratio of fusion power to dissipated power. Tradeoffs for parameters of rf driven steady state reactors are determined....

Short wavelength temperature gradient driven modes in tokamak plasmas.

New unstable temperature gradient driven modes in an inhomogeneous tokamak plasma are identified. These modes represent temperature gradient (ion and electron) driven modes destabilized in the short wavelength regions with k( perpendicular )rho(i,e)>>1, respectively. The instability occurs due to a specific plasma response that significantly deviates from Boltzmann distribution in the regions k...