HTPD 2018

A Heavy Ion Beam Probe (HIBP) diagnostic on the Wendelstein 7-X (W7 X) superconducting stellarator will provide a unique ability to advance understanding of neoclassical and turbulent particle and energy transport. We present results of beam simulations which show that measurement signal levels, calculated using neo-classical density and temperature profiles with central densities up to 1020 m-3, will enable study in the eight W7-X reference magnetic configurations of the equilibrium plasma potential and Er at all radii, and ion-scale fluctuations of ne and potential in the outer plasma region. Elements of the diagnostic design include (1) a beam of thallium or cesium ions having a maximum energy of 2 MeV; (2) injection and detection of the beam through previously allocated ports; (3) a toroidal magnetic field in the + direction of W7-X; and (4) location of all HIBP system components outside of the W7 X cryostat. These design parameters can be realized using the accelerator and energy analyzer of the TEXT-U 2 MeV HIBP (which is now in Greifswald), and beam steering systems having smaller electrodes and electric fields (but higher voltages) than those of the TEXT-U diagnostic. This work is supported by US DoE Award DE-SC0013918.