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The effects of the tube diameter on the discharge ignition and the plasma properties of atmospheric‐pressure microplasma confined inside capillary
Author(s) -
Wu Shuqun,
Wu Fei,
Liu Chang,
Liu Xueyuan,
Chen Yuxiu,
Shao Tao,
Zhang Chaohai
Publication year - 2019
Publication title -
plasma processes and polymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 74
eISSN - 1612-8869
pISSN - 1612-8850
DOI - 10.1002/ppap.201800176
Subject(s) - microplasma , plume , plasma , materials science , capillary action , atmospheric pressure , electron density , analytical chemistry (journal) , ignition system , atomic physics , chemistry , composite material , thermodynamics , physics , meteorology , chromatography , quantum mechanics
With plasma penetration into a capillary and the assistant of an air DBD, an ac‐driven Ar microplasma plume having a length of several cm is generated inside the capillary. The inner diameter of the capillary ranges from 4 to 100 µm. When the tube diameter decreases, the length of the microplasma plume decreases, and while the ignition voltage, the current density, and the electron density increase significantly. For the tube diameter of 9 µm, the current density and the electron density measured from the Stark broadening of H α line reach as high as 10 9 A m −2 and 11 × 10 16 cm −3 , respectively. The microplasma plume is of high degree of ionization and remains non‐thermal. Rather than monotonically increasing, the propagation velocity of the microplasma plume decreases and then keeps almost unchanged after the tube diameter reaches 20 µm.