Development of transient internal probe (TIP) magnetic field diagnostic

The Transient Internal Probe (TIP) is designed to permit measurement of internal magnetic fields in hot, high density plasmas. The concept consists of accelerating a probe to high velocities (2.2 km/s) in order to minimize probe exposure time to plasma. Faraday rotation within the probe measures the local magnetic field. The probe and detection scheme have been tested by dropping the probe through a static magnetic field. Magnetic field resolution of 20 gauss and spatial resolution of 5 mm has been achieved. System frequency response is 10 MHz. A gas interfaced system has also been developed to prevent helium muzzle gas from entering the plasma chamber with the probe. Additionally the probe must be separated from the sabot which protects the probe during acceleration in the gas gun. Data is presented showing the results of various separation techniques. Results of pressure measurements illustrating the effectiveness of the gas interface system is also presented.