Transport Processes and New Modes Introduced with "Heavy" Nuclei Populations

Plasmas in which low density populations of heavy nuclei are present in addition to a majority of light nuclei are a common occurrence. The most frequent (and unavoidable) case is that of an impurity population whose cyclotron frequency, ΩI, differs from that, Ωi, of the main population. On the other hand, as the presented theory suggests and significant experiments confirm, the injection of a heavier population [1] than the majority population may be carried out in order to affect the transport properties [2] of the main population or to optimize the spatial density profiles of the reacting nuclei populations in the case of fusion burning plasmas. In addition to finding new high frequency “impurity” modes, with ω≅ΩI, which can involve significant magnetic fluctuations [3], low frequency electrostatic modes have been shown to transport impurities outward and main nuclei inward in the presence of a significant radial temperature gradient of the latter population. Moreover, a background of excited low frequency modes (ω<<ΩI) can produce anomalous particle and thermal energy transport which can have an important role for the growth of the considered high frequency electromagnetic modes.

[1] C. Mazzotta, et al., Paper IAEA-CN-899 MFE. FEC (IAEA., Vienna, 2021)

[2] B. Coppi, H. Furth, M. Rosenbluth and R. Sagdeev, Phys. Rev. Lett. 17, 377 (1966)

[3] B. Coppi, S. Cowley, et al., Phys. Fluids 29, 4060 (1986)