Basko, Mikhail

Blazevic, A.

Faik, S.

Grushin, A. S.

Maruhn, J. A.

Novikov, V. G.

Ortner, A.

Roth, M.

Tauschwitz, An.

GSI Repository

Radiation-hydrodynamic simulations of foils heated by hohlraum radiation∗S. Faik1, An. Tauschwitz1,4, J. A. Maruhn1,2, M. M. Basko2,3, A. Ortner6, A. Blazˇevic´5, M. Roth6,V. G. Novikov3, and A. S. Grushin31Goethe University, Frankfurt am Main, Germany; 2EMMI, GSI, Darmstadt, Germany; 3KIAM, Moscow, Russia;4HIC for FAIR, Frankfurt, Germany; 5GSI, Darmstadt, Germany; 6TU Darmstadt, GermanyAn attractive way to generate a uniform plasma statefor measurements of the ion stopping power is to heat asample indirectly with the radiation of a millimeter-scalehohlraum. Recently, simulations of such a hohlraum tar-get with an attached carbon foam [1] have been carried outwith the newly developed code RALEF-2D. Now, new sim-ulations are in progress to support another experimental ap-proach at GSI. The target consists of two hohlraums, a pri-mary spherical one irradiated by the PHELIX laser for theindirect X-ray heating of a secondary cylindrical hohlraumwith two attached carbon foils. Simulations of the primaryhohlraum [2] have shown to stay in good accordance withthe experiment. Here we want to present the preliminaryresults of a series of simulations of the secondary hohlraumwith the goal to find the optimum target configuration andto verify the ion stopping measurements [3].The RALEF-2D code solves the one-fluid one-temperat-ure hydrodynamic equations in two spatial dimensions andincorporates thermal conduction as well as radiation trans-port. The applied EOS, thermal conductivity, and spectralopacities were provided by the THERMOS code. Figure1 shows the lateral cut of the simulated Cartesian (x, y)configuration which extends to infinity along the z-axis.Each carbon foil has an initial thickness lf = 1 μm andareal density <ρf lf> = 0.1 mg cm−2. The supposedlyempty parts of the simulated domain were filled with gasesat density ρ = 10−5 g cm−3. The incoming X-rays of theprimary hohlraum were set up in accordance with exper-imental measurements with a peak Planckian temperatureof 93 eV. The X-ray heating ends at t = 5 ns. In the pre-sented preliminary simulation the spectral energy transportby thermal radiation was treated with one frequency group.The final simulation will be done with 24 discrete groupshνi which implies a much longer computational time. Theangular dependence of the radiation intensity was calcu-lated with the S30 method, which offers 960 discrete raydirections over the entire 4π solid angle.Figure 2 shows the free electron density and the LTEionization degree at t = 5.3 ns when the expanding carbonplasma clouds collide. At this time the ablated gold plasmais close to get into the way of the ion beam. Before thecollision the carbon free electron densities are of the orderne ≈ 1 − 4 × 1020 cm−3 with an ionization degree ofZ ≈ 3.2 − 3.8 at plasma temperatures T ≈ 10 − 16 eV.Hence a time window of nearly 6 ns exists with appropriateplasma conditions for the ion stopping measurements.∗ supported by BMBF (Project 05P12RFFTR), HIC for FAIR, EMMIFigure 1: 2D lateral cut of the simulated configuration.Figure 2: Color contour plots of the free electron densityne and the LTE ionization degree Z at t = 5.3 ns, when thecarbon plasma clouds collide at the hohlraum center.References[1] S. Faik et al., HEDP 10 (2014) 47.[2] M. M. Basko et al., GSI Report 2011-03.[3] A. Ortner et al., GSI Report 2013-1.PNI-PP-07 GSI SCIENTIFIC REPORT 2013188 doi:10.15120/GR-2014-1-PNI-PP-07

Radiation-hydrodynamic simulations of foils heated by hohlraum radiation

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Radiation-hydrodynamic simulations of foils heated by hohlraum radiation

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