Characterization of self-generated electromagnetic fields in the coronae of direct-drive ICF implosions and their impact on acceleration phase hydrodynamic instability growth*

Electromagnetic fields are self-generated in the coronae of direct-drive inertial confinement fusion (ICF) implosions through a variety of mechanisms such as plasma pressure gradients and the Biermann battery effect. These fields may affect implosion behavior by redirecting heat fluxes and modifying hydrodynamic instability growth, as well as affecting hot electron transport. To probe these fields, target normal sheath acceleration-based proton radiographs were obtained from thin shell "exploding pusher" implosions at OMEGA. Synthetic proton radiography and field reconstructions are used to assess the strength and structure of the observed fields. In addition, extended magnetohydrodynamic simulations are carried out to understand the relative importance of various field-generation mechanisms like the magnetothermal instability, as well as the effect of the self-generated fields on acceleration phase hydrodynamic instability growth.