On the Mechanism of Ring‐Shape Structure of Plasma Bullet

Xian, Yuezhong; Yue, Yuanfu; Liu, Dawei; Yang, Yong; Lü, Xinpei; Pan, Yuan

doi:10.1002/ppap.201400126

Cited by 19 publications

(16 citation statements)

References 32 publications

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“…The results of simulation show, in qualitative agreement with the experimental data [12], that the streamer radiation flux has (not far from the tube end) a ring-shaped structure, with maximum shifted from the jet axis, when plasma-forming gas is pure helium, and that the addition of air leads to transition to the structure with maximum of the radiation flux placed at the axis.…”

Section: Discussionsupporting

confidence: 84%

“…One of the arguments supporting this conclusion is disappearance of ring-shaped structure when a small amount of molecular or atomic gas is added to helium [7], [8], [10], [12]. One more reason of emergence of ring-shaped structure of helium jets is limitation of streamer width by tube walls or by surrounding gas (e.g., air) with ionization rate much lower than that in helium, the role of Penning reactions not being crucial [18].…”

Section: Introductionmentioning

confidence: 96%

“…In experiment [21] and simulation [22], the structure of a guided streamer during its travel along two counterpropagating helium jets (between two tubes) changed from a ring-shaped one, near the first tube, to a spherical one, in the middle of propagation region, and to a ring-shaped structure again, at approaching to the second tube. In [12], a ring-shaped structure was observed when guided streamers started from an electrode placed outside the tube.…”

Section: Introductionmentioning

confidence: 97%

“…Already the first observation [3] of plasma bullets-streamers guided along the jet axis-revealed a ring profile of their radiation, with maximum of radiation intensity shifted from the axis. In the following works, ring profiles of various radiating states [4]- [12], metastable helium atoms [13], and electrons [14] in helium plasma jets have been observed. Such profiles have been obtained also in simulations of streamers propagating along thin channels of pure helium [15]- [17] and along helium jets (with account of mixing of helium with ambient air) [18]- [20].…”

Section: Introductionmentioning

confidence: 98%

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On the Ring-Shaped Structure of Helium Plasma Jets

Naidis

2015

IEEE Trans. Plasma Sci.

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The results of simulation of positive streamers propagating along plasma jets formed in pure helium and in helium with 3% of air and emerged into ambient air are presented. It is shown, in agreement with the experimental data, that the addition of air leads to disappearance of ring-shaped structure of plasma jet radiation typical to jets of pure helium. The calculated radial profiles of the electron density in channels of streamers propagating in air at nonuniform radial distributions of the gas density are also given. Like in plasma jets, these profiles can have a ring-shaped structure. In both cases, the reason for the formation of ring-shaped structure is radial nonuniformity of the rate of ionization of gas species by electron impact.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

On the Ring-Shaped Structure of Helium Plasma Jets

Naidis

2015

IEEE Trans. Plasma Sci.

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“…Externally applied plasma can be used to both eradicate cells or stimulate cellular activity without skin injury, depending upon dose [26]. Plasma is being investigated for the treatment of chronic wounds [23,[27][28][29][30][31][32][33][34], bacterial infections [34][35][36] dental hygiene [37] and decay [38,39] and as a new and/or adjunct technology in the treatment of cancers [40][41][42][43][44][45][46][47][48][49][50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

Modelling the helium plasma jet delivery of reactive species into a 3D cancer tumour

Szili

Fukuhara

et al. 2017

Plasma Sources Sci. Technol.

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Cold atmospheric plasmas have attracted significant worldwide attention for their potential beneficial effects in cancer therapy. In order to further improve the effectiveness of plasma in cancer therapy, it is important to understand the generation and transport of plasma reactive species into tissue fluids, tissues and cells, and moreover the rates and depths of delivery, particularly across physical barriers such as skin. In this study, helium (He) plasma jet treatment of a 3D cancer tumour, grown on the back of a live mouse, induced apoptosis within the tumour to a depth of 2.8 mm. The He plasma jet was shown to deliver reactive oxygen species through the unbroken skin barrier before penetrating through the entire depth of the tumour. The depth and rate of transport of He plasma jet generated H 2 O 2 , NO 3 − and NO 2 − , as well as aqueous oxygen [O 2 (aq)], was then tracked in an agarose tissue model. This provided an approximation of the H 2 O 2 , NO 3 − , NO 2 − and O 2 (aq) concentrations that might have been generated during the He plasma jet treatment of the 3D tumour. It is proposed that the He plasma jet can induce apoptosis within a tumour by the 'deep' delivery of H 2 O 2 , NO 3 − and NO 2 − coupled with O 2 (aq); the latter raising oxygen tension in hypoxic tissue.

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Plasma “bullet” with hollow structure: formation and evolution

Chang

Zhao

et al. 2018

Sci Rep

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Since the plasma “bullet” and ring shape were discovered by Teschke and coworkers in 2005, the hollow structure of the plasma “bullet” has been a hot topic as an important phenomenon. Clearing the mechanism back on the phenomenon is very important to research and application of atmospheric pressure plasma jet (APPJ). Although a lot of discussions on the generation and evolution of the hollow structure have been conducted in past years, there is a substantial divergence between the experimental researcher and the numerical simulation researcher. The former considers that the Penning effect has a main contribution, because the presence of impurities enables the Penning process to occur at the gas flow/air interface. On the contrary, numerical simulation claims that the Penning effect is not so decisive to the formation of hollow structure. Based on our previous work, this paper aims to clear the debatable topic by setting the special experiments. After comparing and analyzing the phenomena and mechanism, a better comprehension is reached on the contribution of the Penning effect to the hollow structure. We also give a promising conclusion for forming the hollow structure of plasma jet in the end of paper.

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On the Mechanism of Ring‐Shape Structure of Plasma Bullet

Cited by 19 publications

References 32 publications

On the Ring-Shaped Structure of Helium Plasma Jets

On the Ring-Shaped Structure of Helium Plasma Jets

Modelling the helium plasma jet delivery of reactive species into a 3D cancer tumour

Plasma “bullet” with hollow structure: formation and evolution

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