Dynamic smoothing of fuel-target implosion non-uniformity by phase control in heavy ion inertial fusion*

  The dynamic smoothing method is applied to direct-driven fuel target implosion in heavy ion inertial fusion. A dynamic mitigation method was proposed to stabilize plasma instabilities and to smooth plasma non-uniformities based on a phase control [1]. We found that the wobbling motion of heavy ion beam (HIB) axis induces a phase-controlled HIBs energy deposition, and it realizes the phase-controlled implosion acceleration non-uniformity, so that the HIBs illumination non-uniformity is well smoothed [2, 3]. HIB accelerators provide a well-established capability to oscillate HIB axis with a high frequency. In inertial confinement fusion, a fuel implosion uniformity is essentially required to compress the DT fuel and to release the fusion energy. The non-uniformity of the implosion acceleration should be less than a few % [4]. The results in this paper also demonstrate that the wobbling HIBs would provide an improvement in the fusion energy output gain. [1] S. Kawata, Phys. of Plasmas, 19, 024503 (2012). [2] R. Sato, et al., Scientific Reports 9, 6659 (2019). [3] S. Kawata, Advances in Phys. X, 6, 1873860 (2021). [4] S. Kawata and K. Niu, J. Phys. Soc. Jpn., 53, 3416 (1984).