Attractive Non-thermal Fusion Burning Plasma Regimes

Self-organization processes that are present in current experiments of non-burning plasmas can be expected to manifest themselves also through new effects in plasmas where the density and temperature profiles are interconnected with energy deposition (heating) by fusion reaction products. In this context, radially “captive” ballooning modes [1], capable of sustaining the transfer of energy from fusion reaction products to the reacting nuclei, have been identified. These modes, which involve high power transfers with acceptable particle density fluctuation levels, can lead to so-called “cool fusion” scenarios with considerably lower temperatures of the fusing nuclei than those associated with simple Maxwellian distributions. The needed electron temperatures have to be adequate (e.g., around the ideal ignition temperature for DT plasmas) to avoid significant electron damping by the relevant ballooning mode-particle resonances [1]. These findings, which are consistent with recent experimental observations [2], suggest that a serious experimental effort should be devoted to exploit the non-thermal physics of fusion burning regimes.