IShTAR plasma operation and diagnostics

IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetized plasma test facility for RF sheaths studies. The device consists of a cylindrical vacuum vessel with a diameter of 1 m and length of 1.1 m. The plasma is created by an external cylindrical plasma source equipped with a helical antenna. Progress is reported on the plasma optimization and electric field measurements. An interferometer and probes have recently been added to the IShTAR suite of diagnostics. A sensitivity of the electron density to the magnetic topology has been observed, possibly related to the helicon wave propagation. E-field measurements by Passive Optical Emission Spectroscopy were achieved at two viewing locations: a DC biased electrode and the ICRF antenna. The installation of an active Doppler-Free Saturation Spectroscopy diagnostic has started.