Dr Valerian Hall-Chen (A*STAR, Singapore)
DBS measurements of turbulence spectra in Bouncing Ball DIII-D plasmas
Understanding turbulent transport is key for designing future fusion power plants. This requires measurements of turbulent fluctuations. The Doppler backscattering (DBS) diagnostic is one of the few diagnostics which can measure density fluctuations of intermediate length scales. To vary the measured wavevector of the fluctuations, the DBS probe beam is typically steered poloidally shot-to-shot, with the shots being repeated with as similar properties as possible. In this work, we move the plasma vertically, enabling measurements of density fluctuations across a range of wavevectors, within a single shot. We then account for instrumentation effects, finding different turbulence spectra at different radial locations.
Additionally, I will give a brief overview of research in fusion plasmas and diagnostics in A*STAR Singapore, highlighting potential opportunities.