Abstract
Nanosecond Repetitively Pulsed (NRP) discharges in atmospheric pressure water vapor at 450 K are studied with time-resolved optical emission spectroscopy (OES). A 20-ns high- voltage pulse is applied across two pin-shaped electrodes at a frequency of 10 kHz, with an energy of 2 mJ per pulse. Emission of OH(A-X) as well as atomic states of O and H are observed. The emission of these species increases during the 20-ns pulse, then decreases. Then, after about 150 ns, we observe again a strong increase of emission of these species. To determine the gas temperature, we add a small amount (1%) of molecular nitrogen to the flow of water vapor. The rotational temperature measured from N2(C3IIu - B2IIg) second positive system of N2 is measured and compared with the rotational temperature measure with the OH(A-X) transition. The electron density is obtained by the Stark broadening of the Hβ emission line at 486 nm. The electron number density increases to about 6 × 1015cm-3 during the pulse, then decays to 1014cm-3 after 150 ns. But then, a surprising behavior occurs: the Full-Width at Half-Maximum (FWHM) of the Hβ emission line increases again sharply, with no electric field applied, up to 5 nm, and then decays slowly to 1 nm over the next microsecond.
Original language | English (US) |
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Title of host publication | 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013 |
State | Published - 2013 |
Externally published | Yes |
Event | 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013 - Grapevine, TX, United States Duration: Jan 7 2013 → Jan 10 2013 |
Other
Other | 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013 |
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Country/Territory | United States |
City | Grapevine, TX |
Period | 01/7/13 → 01/10/13 |
ASJC Scopus subject areas
- Space and Planetary Science
- Aerospace Engineering