Publications by Archie Bott

Supersonic plasma turbulence in the laboratory.

Nature communications 10 (2019) 1758-

TG White, MT Oliver, P Mabey, M Kühn-Kauffeldt, AFA Bott, LNK Döhl, AR Bell, R Bingham, R Clarke, J Foster, G Giacinti, P Graham, R Heathcote, M Koenig, Y Kuramitsu, DQ Lamb, J Meinecke, T Michel, F Miniati, M Notley, B Reville, D Ryu, S Sarkar, Y Sakawa, MP Selwood, J Squire, RHH Scott, P Tzeferacos, N Woolsey, AA Schekochihin, G Gregori

The properties of supersonic, compressible plasma turbulence determine the behavior of many terrestrial and astrophysical systems. In the interstellar medium and molecular clouds, compressible turbulence plays a vital role in star formation and the evolution of our galaxy. Observations of the density and velocity power spectra in the Orion B and Perseus molecular clouds show large deviations from those predicted for incompressible turbulence. Hydrodynamic simulations attribute this to the high Mach number in the interstellar medium (ISM), although the exact details of this dependence are not well understood. Here we investigate experimentally the statistical behavior of boundary-free supersonic turbulence created by the collision of two laser-driven high-velocity turbulent plasma jets. The Mach number dependence of the slopes of the density and velocity power spectra agree with astrophysical observations, and supports the notion that the turbulence transitions from being Kolmogorov-like at low Mach number to being more Burgers-like at higher Mach numbers.

Thomson scattering cross section in a magnetized, high-density plasma.

Physical review. E 99 (2019) 063204-

AFA Bott, G Gregori

We calculate the Thomson scattering cross section in a nonrelativistic, magnetized, high-density plasma-in a regime where collective excitations can be described by magnetohydrodynamics. We show that, in addition to cyclotron resonances and an elastic peak, the cross section exhibits two pairs of peaks associated with slow and fast magnetosonic waves; by contrast, the cross section arising in pure hydrodynamics possesses just a single pair of Brillouin peaks. Both the position and the width of these magnetosonic-wave peaks depend on the ambient magnetic field and temperature, as well as transport and thermodynamic coefficients, and so can therefore serve as a diagnostic tool for plasma properties that are otherwise challenging to measure.

Laboratory evidence of dynamo amplification of magnetic fields in a turbulent plasma.

Nature communications 9 (2018) 591-

P Tzeferacos, A Rigby, AFA Bott, AR Bell, R Bingham, A Casner, F Cattaneo, EM Churazov, J Emig, F Fiuza, CB Forest, J Foster, C Graziani, J Katz, M Koenig, C-K Li, J Meinecke, R Petrasso, H-S Park, BA Remington, JS Ross, D Ryu, D Ryutov, TG White, B Reville, F Miniati, AA Schekochihin, DQ Lamb, DH Froula, G Gregori

Magnetic fields are ubiquitous in the Universe. The energy density of these fields is typically comparable to the energy density of the fluid motions of the plasma in which they are embedded, making magnetic fields essential players in the dynamics of the luminous matter. The standard theoretical model for the origin of these strong magnetic fields is through the amplification of tiny seed fields via turbulent dynamo to the level consistent with current observations. However, experimental demonstration of the turbulent dynamo mechanism has remained elusive, since it requires plasma conditions that are extremely hard to re-create in terrestrial laboratories. Here we demonstrate, using laser-produced colliding plasma flows, that turbulence is indeed capable of rapidly amplifying seed fields to near equipartition with the turbulent fluid motions. These results support the notion that turbulent dynamo is a viable mechanism responsible for the observed present-day magnetization.

Analytical estimates of proton acceleration in laser-produced turbulent plasmas


KA Beyer, B Reville, AFA Bott, H-S Park, S Sarkar, G Gregori

Evolution of the Design and Fabrication of Astrophysics Targets for Turbulent Dynamo (TDYNO) Experiments on OMEGA


SA Muller, DN Kaczala, HM Abu-Shawareb, EL Alfonso, LC Carlson, M Mauldin, P Fitzsimmons, D Lamb, P Tzeferacos, L Chen, G Gregori, A Rigby, A Bott, TG White, D Froula, J Katz

Implementation of a Faraday rotation diagnostic at the OMEGA laser facility


A Rigby, J Katz, AFA Bott, TG White, P Tzeferacos, DQ Lamb, DH Froula, G Gregori

Proton imaging of stochastic magnetic fields


AFA Bott, C Graziani, P Tzeferacos, TG White, DQ Lamb, G Gregori, AA Schekochihin

Numerical modeling of laser-driven experiments aiming to demonstrate magnetic field amplification via turbulent dynamo

PHYSICS OF PLASMAS 24 (2017) ARTN 041404

P Tzeferacos, A Rigby, A Bott, AR Bell, R Bingham, A Casner, F Cattaneo, EM Churazov, J Emig, N Flocke, F Fiuza, CB Forest, J Foster, C Graziani, J Katz, M Koenig, C-K Li, J Meinecke, R Petrasso, H-S Park, BA Remington, JS Ross, D Ryu, D Ryutov, K Weide, TG White, B Reville, F Miniati, AA Schekochihin, DH Froula, G Gregori, DQ Lamb