Digital holographic interferometry employing Fresnel transform reconstruction for the study of flow shear stabilized Z-pinch plasmas
The ZaP-HD Flow Z-Pinch project provides a platform to explore how shear flow stabilized Z-pinches could scale to high-energy-density plasma (HEDP) and fusion reactor conditions. ZaP-HD generates shear stabilized, axisymmetric Z-pinches with stable lifetimes approaching $60$$$$\mu$$s. The goal of the project is to increase the plasma density and temperature compared to the previous ZaP project by compressing the plasma to smaller radii ($$\approx 1$$ mm). Radial and axial plasma electron density structure is measured using digital holographic interferometry (DHI), which provides the necessary fine spatial resolution. ZaP-HD's DHI system uses a 2 ns Nd:YAG laser pulse with a second harmonic generator ($$\lambda = 532$$ nm) to produce holograms recorded by a Nikon D3200 digital camera. The holograms are numerically reconstructed with the Fresnel transform reconstruction method to obtain the phase shift caused by the interaction of the laser beam with the plasma. This provides a two-dimensional map of line-integrated electron density, which can be Abel inverted to determine the local number density. The DHI resolves line-integrated densities down to $$3\times 10^{20}$$ m$$^{-2}$$ with spatial resolution near $$10 \mu$$m. This work presents the first application of Fresnel transform reconstruction as an analysis technique for a plasma diagnostic, and it analyzes the method's accuracy through study of synthetic data. It then presents an Abel inversion procedure that utilizes data on both sides of a Z-pinch local number density profile to maximize profile symmetry. Error estimation and Abel inversion are applied to measured data.
- Research Organization:
- Univ. of Washington, Seattle, WA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- NA0001860; FG02-04ER54756
- OSTI ID:
- 1465208
- Alternate ID(s):
- OSTI ID: 1328714
- Journal Information:
- Review of Scientific Instruments, Vol. 87, Issue 10; ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
A methodology for the digital reconstruction of an interferogram, a schlieren image, or a shadowgram from a single digital holographic recording
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journal | December 2018 |
Progress Toward a Compact Fusion Reactor Using the Sheared-Flow-Stabilized Z-Pinch
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journal | July 2019 |
Sustained Neutron Production from a Sheared-Flow Stabilized Pinch
|
journal | April 2019 |
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