Digital holographic interferometry employing Fresnel transform reconstruction for the study of flow shear stabilized Z-pinch plasmas

Abstract

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 (plasma with pressures exceeding 1 Mbar) and fusion reactor conditions. The Z-pinch is a linear plasma confinement geometry in which the plasma carries axial electric current and is confined by its self-induced magnetic field. ZaP-HD generates shear stabilized, axisymmetric Z-pinches with stable lifetimes approaching 60 μs. 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 (≈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 (λ = 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 × 10 m with spatial resolution near 10 μm. This paper 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 the measured data.

Modeling electron interference at the neuronal membrane yields a holographic projection of representative information content

“…Electromagnetic point sources can be modeled as interfering object and reference waves on a two-dimensional holographic recording surface Classical holograms are formed by the interference of light waves, with the information encoded on a two-dimensional surface and projected into a threedimensional volume [32,33]. It is worth noting that these principles can be extrapolated to any wave-like particle, to generate a hologram of the electrical field [44]. A photon, an electron, or even an entire ion, can be represented as the point source of an electromagnetic field, with the amplitude and phase of the wave represented by its absolute value and relative angle.…”

Sustained Neutron Production from a Sheared-Flow Stabilized Z Pinch

“…The plasma density profile is measured using a digital holographic interferometer. 25,26 An image of the line-integrated plasma density profile is shown in Fig. 3 Plasma temperature in the pinch is measured by ion Doppler spectroscopy based on spectra of impurity ions, such as carbon.…”

“…The plasma density profile is measured using a digital holographic interferometer. 25,26 An image of the line-integrated plasma density profile is shown in Fig. 3(a).…”