Speaker
Chandra Curry
(SLAC National Accelerator Laboratory/University of Alberta)
Description
Self-generated magnetic fields are produced in high-intensity laser-plasma experiments from several mechanisms, including relativistic electron currents and misaligned density and temperature gradients (the Biermann Battery effect). Understanding the formation and timescales of these magnetic fields is important in several high energy density regimes ranging from astrophysical jets to the fast ignition approach to laser fusion energy. Here we will present a study of the magnetic fields produced in cylindrical geometry using wire targets (10-25µm in diameter) with the Titan laser (700fs, 50 J) at the Jupiter Laser Facility. The spatial and energy distributions of the laser accelerated protons produced in the interaction are recorded using radiochromatic film (RCF) and Thomson Parabola ion spectrometers, respectively. A cylindrical RCF stack was installed around the wire target which provided a large-angle sampling of the spatial distribution. Two well-defined bands, offset ±8-15° vertically from the laser plane and surrounding the wire azimuthally, are observed for proton energies up to 7.5 MeV. We will show that the two bands observed on the RCF can be attributed to the formation of caustics in linear proton radiography theory whereby the energetic protons are deflected due to the self-generated magnetic fields. Finally, these results will be compared with 2D and 3D Particle-in-cell (PIC) simulations which qualitatively reproduce the observed bands with magnetic fields on the order of 10 MG due to the Biermann Battery effect.
*This work was supported by the U.S. DOE Office of Science, Fusion Energy Science under FWP 100182 and by SLAC Laboratory Directed Research and Development. Additional support was provided by LLNL under contract DE-AC52-07NA27344 and the U.S. DOE Office of Science, Fusion Energy Science ACE HEDLP Diagnostics.*
Primary author
Chandra Curry
(SLAC National Accelerator Laboratory/University of Alberta)
Co-authors
Adrienne Propp
(SLAC National Accelerator Laboratory)
Arthur Pak
(Lawrence Livermore National Laboratory)
Bastian Aurand
(Heinrich-Heine-University Düsseldorf)
Bhuvanesh Ramakrishna
(Indian Institute of Science Education and Research, Bhopal)
Charles Ruyer
(SLAC National Accelerator Laboratory)
Christian Roedel
(SLAC National Accelerator Laboratory)
Clement Goyon
(Lawrence Livermore National Laboratory)
Frederico Fiuza
(SLAC National Accelerator Laboratory)
Jackson Williams
(Lawrence Livermore National Laboratory)
John Ruby
(Lawrence Livermore National Laboratory)
Jongjin Kim
(SLAC National Accelerator Laboratory)
Maxence Gauthier
(SLAC National Accelerator Laboratory)
Oswald Willi
(Heinrich-Heine-University Düsseldorf)
Rohini Mishra
(SLAC National Accelerator Laboratory)
Sebastian Goede
(SLAC National Accelerator Laboratory)
Shaun Kerr
(Lawrence Livermore National Laboratory/University of Alberta)
Siegfreid Glenzer
(SLAC National Accelerator Laboratory)
Ying Tsui
(University of Alberta)
