Session RP1 - Poster Session VIII.
POSTER session, Thursday afternoon, October 30
Fran Hill Southeast Exhibit Hall, ACC
Heavy Ion Beam Probe (HIBP) is a very powerful tool that is able to simultaneously detect potential, density, magnetic field and their fluctuations in interior of high temperature plasmas. In CHS, so far, the HIBP has revealed interesting behavior of the plasma interior, such as bifurcation, internal transport barrier, MHD phenomena, by observing potential profile and density fluctuation. Now we are making efforts to make a full use of the other abilities of HIBP, that is, to detect potential fluctuation and magnetic field fluctuation. In order to study potential fluctuation, a new ion source has been developed to increase beam current density. With the new ion source, we have obtained current 3~5 times larger than the previous one. This improvement allows us to detect the potential fluctuation, and also density fluctuation with higher S/N ratio. As for the magnetic field fluctuation estimated from the beam displacement, the interpretation of the signal is quite difficult because of 3D magnetic field configuration of CHS. In the first place, a numerical calculation has been performed in axisymmetric toroidal field i. e., tokamak configuration, in order to obtain a basic perspective of the relationship between the beam displacement and local magnetic field fluctuation. In our presentation, we will describe the resultant progress of HIBP measurements, and the recent results of density and potential fluctuation measurements in the CHS stellarater.