Title: Combined microwave and laser Rayleigh scattering diagnostics for pin-to-pin nanosecond discharges

Abstract

In this work, the temporal decay of electrons produced by an atmospheric pin-to-pin nanosecond discharge operating in the spark regime was measured via a combination of microwave Rayleigh scattering (MRS) and laser Rayleigh scattering (LRS). Due to the initial energy deposition of the nanosecond pulse, a variation in the local gas density occurs on the timescale of electron decay. Thus, the assumption of a constant collisional frequency is no longer applicable when electron number data are extracted from MRS measurements. Furthermore, to recalibrate MRS measurements throughout the electron decay period, temporally resolved LRS measurements of the local gas density were performed over the event duration. The local gas density was calculated to be 30% of the ambient level during the later stages of electron decay, and it recovers at about 1 ms after discharge. A shock front traveling approximately 500 m/s was additionally observed. Coupled with plasma volume calibration via temporally resolved intensified charge-coupled device imaging, the corrected decay curves of the electron number and electron number density are presented with a measured peak electron number density of 4.5 × 1015 cm^-3 and a decay rate of ~(0.1–0.35) × 10⁷ s^-1. A hybrid MRS and LRS diagnostic technique can bemore » applied for a broad spectrum of atmospheric-pressure microplasmas where a variation in the gas number density is expected due to energy deposition in the discharge.« less

Authors:

Wang, Xingxing  ^[1];

• Search DOE PAGES for author "Wang, Xingxing"
• Search DOE PAGES for ORCID "0000-0002-8173-7148"

Patel, Adam  ^[1];

• Search DOE PAGES for author "Patel, Adam"
• Search DOE PAGES for ORCID "0000-0003-0075-3726"

Shashurin, Alexey  ^[1]

• Search DOE PAGES for author "Shashurin, Alexey"
• Search DOE PAGES for ORCID "0000-0003-2980-8954"

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+ Show Author Affiliations

1. Purdue Univ., West Lafayette, IN (United States). School of Aeronautics and Astronautics

Publication Date:

Mon May 10 00:00:00 EDT 2021

Research Org.:

Purdue Univ., West Lafayette, IN (United States)

Sponsoring Org.:

USDOE Office of Science (SC); National Science Foundation (NSF)

OSTI Identifier:

1852515

Alternate Identifier(s):

OSTI ID: 1782383

Grant/Contract Number:  

SC0018156; 1903415

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 129; Journal Issue: 18; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Physics; shock waves; density measurement; optical scattering; microwaves; plasma diagnostics