thirty seconds (determined by the setting of VRJ, which allows condenser C2 to charge up to its full high voltage, V2 ikes and relay RLB operates:(i) opening RLB, and releasing relay RLA;(ii) closing RLB,. 3. Closure of RLB, applies a negative pulse to the control grid of the cold cathode tetrode V,, as a result of which the anode to cathode path immediately becomes conducting, and condenser C8 discharges through the primary of the ignition coil TR4. This produces in the secondary a damped oscillatory transient with an initial highly positive peak which, applied to the trigger electrode, flashes the discharge tube.4. Release of relay R L A restores the negative bias to V, $0 that the ax. energized relay RLB is released, and, after a short interval for recharging C8, the circuit conditions prior to operation of SW3 are resumed.A two-minute thermal delay switch S W, prevents application of anode voltage to the gas triode V2 until its heater has warmed up.

No abstract

No abstract

We present an alternative way to write the Euler equations for an ideal isentropic fluid as a symmetric hyperbolic system of evolution equations for a timelike vector field. An equation of state has to be provided which relates the length of this vector to the sound velocity. The relation to the conventional formulation is established and some of the consequences are discussed.

The X-ray spectrometer used in high-energy-density plasma experiments generally requires both broad X-ray energy coverage and high temporal, spatial, and spectral resolutions for overcoming the difficulties imposed by the X-ray background, debris, and mechanical shocks. By using an elliptical crystal together with a streak camera, we resolve this issue at the SG-II laser facility. The carefully designed elliptical crystal has a broad spectral coverage with high resolution, strong rejection of the diffuse and/or fluorescent background radiation, and negligible source broadening for extended sources. The spectra that are Bragg reflected (23 • < θ < 38 • ) from the crystal are focused onto a streak camera slit 18 mm long and about 80 µm wide, to obtain a time-resolved spectrum. With experimental measurements, we demonstrate that the quartz(1011) elliptical analyzer at the SG-II laser facility has a single-shot spectral range of (4.64-6.45) keV, a typical spectral resolution of E/∆E = 560, and an enhanced focusing power in the spectral dimension. For titanium (Ti) data, the lines of interest show a distribution as a function of time and the temporal variations of the He-α and Li-like Ti satellite lines and their spatial profiles show intensity peak red shifts. The spectrometer sensitivity is illustrated with a temporal resolution of better than 25 ps, which satisfies the near-term requirements of high-energy-density physics experiments.