Proton Radiography of Electromagnetic Fields Associated with Imploded ICF capsules and Laser-Irradiated Hohlraums*

Time-gated, mono-energetic-proton radiography provides unique measurements of electric (E) and magnetic (B) fields in laser-produced plasmas of imploded ICF capsules and in laser-irradiated hohlraums. These experiments resulted in the first observations of several new and important features previously unrealized [1-5]: first, the observation of radial electric fields inside the imploding capsule that are initially directed inward (at $\sim $10$^{9 }$V/m), reversing direction ($\sim $10$^{8 }$V/m) near deceleration onset, and are likely related to the evolution of the electron pressure gradient; second, the observation of many radial filaments with complex electromagnetic field striations and bifurcations, permeating the entire field of view, and third, the observation of electric fields up to $\sim $ 10$^{9 }$V/m in laser-irradiated gold hohlraums. In addition, these experiments also provide critical information about plasma areal density, both in direct-drive spherical or cone-in-shell targets, during the different times from acceleration, through coasting, deceleration, to final stagnation, thereby providing a comprehensive picture of ICF capsule implosion dynamics. [1] C. K. Li \textit{et al.,} Phys. Rev. Lett. \underline {97}, 135003 (2006), [2] C. K. Li \textit{et al.,} Phys. Rev. Lett. \underline {99}, 015001 (2007). [3] C. K. Li \textit{et al.,} Phys. Rev. Lett. \underline {99}, 055001 (2007). [4] J. R. Rygg \textit{et al., }Science \underline {319}, 1223 (2008). [5] C. K. Li \textit{et al.,} Phys. Rev. Lett. \underline {100} 225001 (2008). \newline \newline *This work was performed in part at the LLE National Laser User's Facility (NLUF), and was supported in part by US DOE, LLNL, LLE, and the Fusion Science Center at Univ. Rochester. \newline \newline **In collaboration with F. H. S\'{e}guin, J. A. Frenje, M. Manuel, D. Casey, N. Sinenian, and R. D. Petrasso (MIT), R. Betti, J. Delettrez, J. P. Knauer, F. Marshall, D. D. Meyerhofer, T. Sangster, D. Shvarts, V. A. Smalyuk, J. A. Soures, and C. Stoeckl (LLE), P. A. Amendt, J. R. Rygg, R. P. J. Town, and O. L. Landen (LLNL), A. Nikroo, C. A. Back, and J. D. Kilkenny (GA).