Time-resolved and multiple-angle Thomson scattering on gas-puff Z-Pinch plasmas at pinch time

Journal Article · Fri Oct 19 00:00:00 EDT 2018 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.5038879· OSTI ID:1614452

Rocco, Sophia V. R.  ^[1]; Banasek, Jacob T.  ^[1]; Potter, William M. ^[1]; Hammer, David A.  ^[1]

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1. Cornell Univ., Ithaca, NY (United States). Lab. of Plasma Studies

A 526.5 nm Thomson scattering diagnostic laser enables probing of the plasma conditions of neon gas-puff z-pinch implosions with temporal resolution. Splitting the laser into two 2.5 J pulses, both 2.3 ns in duration and separated by 4 ns, allows observation of sub-nanosecond time-resolved spectra for a total time of 7 ns. Collection optics were set at 90° and 30° to the laser, observing the same on-axis scattering volume with a radial extent of 0.4 mm. The spectra from both angles were collected by using the same streak camera, using a coupling system that allowed us to obtain temporal, spectral, and angular resolution in the same image. By comparing the ion-acoustic spectra from the two angles, we determined electron temperature and a range of possible electron densities. Measurements made in the 1-3 ns period before pinch time show best fit (determined by a least-squares method) electron densities of around 2 × 10¹⁹ cm^-3, increasing to 1.5 × 10²⁰ cm^-3 in the 3 ns following the start of the x-ray burst (t = 0 ns) from the pinch. The electron temperature increases from 300 eV to 500 eV at t = 0 ns before decreasing to below 300 eV after pinch time. With the present parameters (probe beam, collection angles, and electron temperature and density), this diagnostic method is too insensitive to electron density to provide more than a constraint on that parameter. Plasma regimes in which this technique could determine electron density with some precision are calculated.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0001836; NA0003764; B619181
• OSTI ID: 1614452
• Alternate ID(s): OSTI ID: 1478279
• Journal Information: Review of Scientific Instruments, Vol. 89, Issue 10; ISSN 0034-6748
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Instruments & Instrumentation
Physics
Thomson scattering
Streak cameras
Electron density