title: Observations of electromagnetic fields and plasma flow in hohlraums with proton radiography.
abstract: We report on the first proton radiography of laser-irradiated hohlraums. This experiment, with vacuum gold (Au) hohlraums, resulted in observations of self-generated magnetic fields with peak values approximately 10;{6} G. Time-gated radiographs of monoenergetic protons with discrete energies (15.0 and 3.3 MeV) reveal dynamic pictures of field structures and plasma flow. Near the end of the 1-ns laser drive, a stagnating Au plasma (approximately 10 mg cm;{-3}) forms at the center of the hohlraum. This is a consequence of supersonic, radially directed Au jets (approximately 1000 microm ns;{-1}, approximately Mach 4) that arise from the interaction of laser-driven plasma bubbles expanding into one another.
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.forename: F H
authors.initials: FH
authors.lastname: Séguin
authors.forename: J A
authors.initials: JA
authors.lastname: Frenje
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso
authors.forename: P A
authors.initials: PA
authors.lastname: Amendt
authors.forename: R P J
authors.initials: RP
authors.lastname: Town
authors.forename: O L
authors.initials: OL
authors.lastname: Landen
authors.forename: J R
authors.initials: JR
authors.lastname: Rygg
authors.forename: R
authors.initials: R
authors.lastname: Betti
authors.forename: J P
authors.initials: JP
authors.lastname: Knauer
authors.forename: D D
authors.initials: DD
authors.lastname: Meyerhofer
authors.forename: J M
authors.initials: JM
authors.lastname: Soures
authors.forename: C A
authors.initials: CA
authors.lastname: Back
authors.forename: J D
authors.initials: JD
authors.lastname: Kilkenny
authors.forename: A
authors.initials: A
authors.lastname: Nikroo