In high temperature plasmas, fusion energy is released only as a result of close collisions between nuclei (i.e. small impact parameter, energetic collisions). Likewise, in strongly magnetized pure electron or pure ion plasmas, the cyclotron energy for a charge is bound up in small high frequency cyclotron orbits, and is released only as a result of close collisions. Single species plasmas can be prepared in a state where the initial cyclotron energy is much larger than the energy of motion parallel to the magnetic field, so the cyclotron energy that is released in close collisions heats the parallel motion. One may therefore think of cyclotron energy as being analogous to nuclear energy. The investigators will use this analogy to carry out experimental and theoretical investigations relevant to fusion physics. In particular, they will measure, for the first time, the strong enhancement of the nuclear reaction rate in strongly coupled plasmas. This "screening" enhancement was predicted by Salpeter in 1954, and is particularly important for fusion at high densities, such as in white dwarf stars. In addition the investigators will study "burn dynamics" using strongly magnetized plasmas, and carry out theory relevant for both experiments. The experiments will be conducted on the IV apparatus of the non-neutral plasma physics group in the Physics Department of UCSD, and on the Penning ion trap facility at NIST, Boulder, CO. The work makes strong interdisciplinary connections, with plasma physics, astrophysics, and nuclear physics.
