| Autor: |
Parkevich, E V, Medvedev, M A, Khirianova, A I, Ivanenkov, G V, Selyukov, A S, Agafonov, A V, Shpakov, K V, Oginov, A V |
| Předmět: |
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| Zdroj: |
Plasma Sources Science & Technology; Dec2019, Vol. 28 Issue 12, p1-12, 12p |
| Abstrakt: |
By employing multi-frame laser interferometry, shadow, and schlieren imaging, we trace the formation of a nanosecond spark discharge in millimeter-sized air gaps formed by a point cathode and flat anode or vice-versa. We discover that the electrical breakdown of the discharge gap is associated with extremely fast (≪1 ns) explosive formation of micron-sized cathode and anode spots. We find that the characteristic delay between the instants of the anode and cathode spot initiation can be much shorter than 1 ns. The spots appear as highly ionized near-electrode plasmas with an electron density ne ∼ 1019–1020 cm−3. The spots then give rise to highly ionized spark channels with pronounced filamentary structures. Our findings indicate that the extremely fast formation of anode spots is associated with an ultrafast gap breakdown promoted by an ultrafast ionization wave (UFIW). The role of the UFIW governed by the rapidly evolving cathode spot is discussed as a fundamental mechanism of the breakdown. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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