Digital image analysis of four-frame holographic plasma and neutral gas interferograms
Technical Report
·
OSTI ID:5965275
Diagnostic interferograms characterizing the dynamics of plasma and neutral in the anode-cathode gap of magnetically insulated transmission lines (MITL) are well suited for digital image analysis. The presence of plasma or a neutral gas near the cathode surface produces bending of a pattern of background fringes on the interferogram; the fringes would be straight and uniformly spaced in the absence of such a perturbation. Because the fringes are periodic, we can perform a Fast Fourier Transform (FFT) and extract the phase of the dominant spatial frequency component of the fringe pattern. The fringe phase shift is proportional to the plasma electron or neutral gas density. Futhermore, the location of the plasma-cathode interface can be estimated from the interferogram so that electron density as a function of distance from the cathode surface can be computed. This report introduces the technical problem, examines the image analysis algorithm and presents diagnostic interferogram analysis results. The ability to reliably extract and estimate quantitative parameters from interferograms via digital image analysis is emphasized. This image analysis technique is applicable to a broad class of interferograms where a background fringe pattern is distorted by the refractive index of a plasma or gas.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5965275
- Report Number(s):
- SAND-84-2124; ON: DE85008397
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
640410 -- Fluid Physics-- General Fluid Dynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
99 GENERAL AND MISCELLANEOUS
990200* -- Mathematics & Computers
ALGORITHMS
FOURIER TRANSFORMATION
HOLOGRAPHY
IMAGE PROCESSING
INTEGRAL TRANSFORMATIONS
MATHEMATICAL LOGIC
MATRICES
PLASMA DIAGNOSTICS
PROCESSING
TRANSFORMATIONS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
99 GENERAL AND MISCELLANEOUS
990200* -- Mathematics & Computers
ALGORITHMS
FOURIER TRANSFORMATION
HOLOGRAPHY
IMAGE PROCESSING
INTEGRAL TRANSFORMATIONS
MATHEMATICAL LOGIC
MATRICES
PLASMA DIAGNOSTICS
PROCESSING
TRANSFORMATIONS