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Abstract We report the optical characterization of nanosecond-pulsed plasma ignited directly in liquid nitrogen. Using imaging and optical emission spectroscopy, we estimate neutral temperatures and densities, as well as local electric field values, and the obtained results indicate that the discharge develops via streamer (‘electronic’) mechanism. We show that millimeter-scale plasma propagates in liquid nitrogen at velocities of ∼500 km s−1with the corresponding required local electric fields as high as 25 MV cm−1, while the estimated local electric fields in the ‘core’ of the discharge are around 6–8 MV cm−1(corresponding to reduced electric field values of 600–1000 Td). The neutral and electron densities in the ‘main body’ of the discharge were estimated using broadened argon lines, indicating that the neutral densities in the near-electrode region are around 1020cm−3(tens of atmospheres), while the maximum recorded temperature is just a few tens of degrees above the surrounding liquid. Electron densities were estimated to be ∼1017cm−3, about two orders of magnitude lower than those measured for water discharge.
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Effects of liquid properties on the development of nanosecond-pulsed plasma inside of liquid: comparison of water and liquid nitrogen
Abstract In this manuscript, we report on observations of the development of nanosecond-pulsed plasma in liquids and examine liquids with two drastically different properties: water and liquid nitrogen. Here, we compare the discharge appearance using high-speed imaging, examine bubble formation using shadow imaging, and measure the time-averaged optical emission spectra of these plasmas. Because the liquid nitrogen plasma is ignited in a liquid that is at boiling temperature, we also study the water discharge at various temperatures, up to boiling. We demonstrate that the discharge development appears not to be affected by this type of liquid. Optical emission, however, is strikingly different: in water, we observe continuum emission in the UV region only and no black-body continuum or atomic lines, whereas the liquid nitrogen spectrum is populated by molecular and longer wavelength broadband emissions.
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- Award ID(s):
- 2108117
- PAR ID:
- 10489161
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Physics D: Applied Physics
- Volume:
- 57
- Issue:
- 17
- ISSN:
- 0022-3727
- Format(s):
- Medium: X Size: Article No. 175203
- Size(s):
- Article No. 175203
- Sponsoring Org:
- National Science Foundation
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