Collective optical Thomson scattering in pulsed-power driven high energy density physics experiments (invited)

Suttle, L.; Hare, Jack; Halliday, J. W. D.; Merlini, S.; Russell, D. R.; Tubman, Eleanor; Valenzuela-Villaseca, V.; Rozmus, W.; Bruulsema, C.; Lebedev, S. V.

doi:10.1063/5.0041118

Cited by 20 publications

(11 citation statements)

References 45 publications

(63 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A quantitative comparison would require a measurement of the ion and electron temperatures, which can be accomplished in future experiments via optical Thompson scattering (OTS) (Suttle et al. 2021).…”

Section: Discussion Of Resultsmentioning

confidence: 99%

The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows

et al. 2022

View full text Add to dashboard Cite

We investigate three-dimensional (3-D) bow shocks in a highly collisional magnetized aluminium plasma, generated during the ablation phase of an exploding wire array on the MAGPIE facility (1.4 MA, 240 ns). Ablation of plasma from the wire array generates radially diverging, supersonic ( $M_S \sim 7$ ), super-Alfvénic ( $M_A > 1$ ) magnetized flows with frozen-in magnetic flux ( $R_M \gg 1$ ). These flows collide with an inductive probe placed in the flow, which serves both as the obstacle that generates the magnetized bow shock, and as a diagnostic of the advected magnetic field. Laser interferometry along two orthogonal lines of sight is used to measure the line-integrated electron density. A detached bow shock forms ahead of the probe, with a larger opening angle in the plane parallel to the magnetic field than in the plane normal to it. Since the resistive diffusion length of the plasma is comparable to the probe size, the magnetic field decouples from the ion fluid at the shock front and generates a hydrodynamic shock, whose structure is determined by the sonic Mach number, rather than the magnetosonic Mach number of the flow. The 3-D simulations performed using the resistive magnetohydrodynamic (MHD) code Gorgon confirm this picture, but under-predict the anisotropy observed in the shape of the experimental bow shock, suggesting that non-MHD mechanisms may be important for modifying the shock structure.

show abstract

Section: Discussion Of Resultsmentioning

confidence: 99%

The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Time-gating was provided by an intensified CCD and the exposure time was 4 ns. A more detailed description of the diagnostic is given in [28].…”

Section: Diagnosis Of Temperature and Velocity Profiles With Optical ...mentioning

confidence: 99%

Investigating radiatively driven, magnetised plasmas with a university scale pulsed-power generator

Halliday¹,

Crilly²,

Chittenden³

et al. 2022

Preprint

View full text Add to dashboard Cite

We present first results from a novel experimental platform which is able to access physics relevant to topics including indirect-drive magnetised ICF; laser energy deposition; various topics in atomic physics; and laboratory astrophysics (for example the penetration of B-fields into HED plasmas). This platform uses the X-Rays from a wire array Z-Pinch to irradiate a silicon target, producing an outflow of ablated plasma. The ablated plasma expands into ambient, dynamically significant B-fields (∼ 5 T) which are supported by the current flowing through the Z-Pinch. The outflows have a well-defined (quasi-1D) morphology, enabling the study of fundamental processes typically only available in more complex, integrated schemes. Experiments were fielded on the MAGPIE pulsed-power generator (1.4 MA, 240 ns rise time). On this machine a wire array Z-Pinch produces an X-Ray pulse carrying a total energy of ∼ 15 kJ over ∼ 30 ns. This equates to an average brightness temperature of around 10 eV on-target.

show abstract

“…Ours are not the only experiments pursuing laboratory-scale magnetized shocks, recent z-pinch experiments at the MAGPIE facility [21][22][23] have demonstrated shock formation in the interaction of a magnetized plasma with initially unmagnetized, conducting obstacles, as well as in the interaction of a magnetized plasma with an external, magnetized obstacle at laboratory scales. And, more similar to our experiments, Rigby et al 24 provide evidence of magnetized shock formation in the interaction of a laser-produced plasma with a magnetized sphere.…”

Section: Introductionmentioning

confidence: 99%

Experimental observations of detached bow shock formation in the interaction of a laser-produced plasma with a magnetized obstacle

Levesque,

Liao,

Hartigan

et al. 2022

Preprint

View full text Add to dashboard Cite

The magnetic field produced by planets with active dynamos, like the Earth, can exert sufficient pressure to oppose supersonic stellar wind plasmas, leading to the formation of a standing bow shock upstream of the magnetopause, or pressure-balance surface. Scaled laboratory experiments studying the interaction of an inflowing solar wind analog with a strong, external magnetic field are a promising new way to study magnetospheric physics and to complement existing models, although reaching regimes favorable for magnetized shock formation is experimentally challenging. This paper presents experimental evidence of the formation of a magnetized bow shock in the interaction of a supersonic, super-Alfvénic plasma with a strongly magnetized obstacle at the OMEGA laser facility. The solar wind analog is generated by the collision and subsequent expansion of two counterpropagating, laser-driven plasma plumes. The magnetized obstacle is a thin wire, driven with strong electrical currents. Hydrodynamic simulations using the FLASH code predict the colliding plasma source meets the criteria for bow shock formation. Spatially resolved, optical Thomson scattering measures the electron number density, and optical emission lines provide a measurement of the plasma temperature, from which we infer the presence of a fast magnetosonic shock far upstream of the obstacle. Proton images provide a measure of large-scale features in the magnetic field topology, and reconstructed pathintegrated magnetic field maps from these images suggest the formation of a bow shock upstream of a the wire and as a transient magnetopause. We compare features in the reconstructed fields to two-dimensional MHD simulations of the system.

show abstract

Collective optical Thomson scattering in pulsed-power driven high energy density physics experiments (invited)

Cited by 20 publications

References 45 publications

The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows

The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows

Investigating radiatively driven, magnetised plasmas with a university scale pulsed-power generator

Experimental observations of detached bow shock formation in the interaction of a laser-produced plasma with a magnetized obstacle

Contact Info

Product

Resources

About