Test of the Telegraph Equation for Transport Dynamics in Plasma

Abstract

We have tested the telegraph equation for transport dynamics in magnetized plasma by comparing its results with experimental observations in the Large Helical Device [S. Inagaki et al., Nucl. Fusion 53, 113006 (2013)]. The telegraph equation includes a finite relaxation time for turbulence intensity in response to the changes in global plasma parameters. This model was applied to nondiffusive radial heat pulse propagation under the periodic modulation of the heating power. The model showed some success in reproducing the amplitudes of higher harmonics. However, the phase relation between the temperature gradient and heat flux was opposite to that in experimental observations.

The diffusion limit of ballistic transport in the scrape-off layer

“…which is the telegraph equation. The telegraph equation has been used before to study nonlocal heat transport in the core of fusion plasmas [31][32][33] and zonal flow propagation [34].…”

Approaches to Hysteresis of Transport Relations in Toroidal Plasmas

“…While the telegraph equation can reproduce fast propagation dynamics in various problems, this model does not adequately explain the observation of transport hysteresis. The telegraph equation model explains the fast propagation of change; however, the phase relationship between the temperature gradient and the heat flux is opposite to that in experimental observations [20].…”