Theoretical parametric investigation of plasma sustained by traveling electromagnetic wave in coaxial configuration

Bogdanov, Todor; Benova, E

doi:10.1016/j.vacuum.2018.06.010

Cited by 2 publications

(7 citation statements)

References 10 publications

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“…(ii) Conditions ensuring sustaining an SWD as determined from the characteristics of the phase diagram Benova and collaborators in Sofia (Bulgaria) [37,38,40,41] developed a general and rather straightforward method to find ( fR) min , the value that corresponds to the beginning of an SWD of a given azimuthal mode, given the plasma configuration. Once the corresponding phase diagram is numerically available, they examine the evolution of its aspect as a function of the dimensionless parameter σ≡ωR/c, and then set two specific conditions for an SWD to exist, which are: (i) Zakrzewski's discharge stability criterion [42].…”

Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

“…Although the phase curves for the m=1 and m=2 modes are very similar, the plasma density of the dipolar mode is higher and the plasma column longer than that of the m=2 mode. Under these conditions, it seems that multi-mode regime of operation is possible as m=0 and m=1 modes can propagate and sustain plasma at the same time [41].…”

Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

“…(3) The vacuum-plasma configuration (hollow plasma) This is a 1/r transform of the plasma-vacuum configuration of case 1 above [41]. The m=0 mode can only sustain an SWD provided σ is larger than≈1.56, corresponding to (?fR) min ≈7.45 GHz-cm, requiring a high SW frequency and a large plasma radius.…”

Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

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Contribution of surface-wave (SW) sustained plasma columns to the modeling of RF and microwave discharges with new insight into some of their features. A survey of other types of SW discharges

Moisan¹,

Nowakowska²

2018

Plasma Sources Sci. Technol.

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maintenance E-field sustaining the discharge comes out as an internal parameter, i.e. it is operator independent, in contrast to what is generally believed whatever the kind of E-field sustained discharges; (ii) the smaller the volume in which power is absorbed with respect to the volume in which it is spent, the higher the intensity of the maintenance E-field: this leads to higher atomic (molecular) excitation rates inside than outside the absorption region (such is the case in microdischarges); (iii) the value of θ L varies significantly with the SW field frequency, decreasing with increasing frequency from the RF domain to that of microwaves; (iv) the power lost θ L , which is the power cost to sustain an electron-ion pair in an SWD, can serve to evaluate the efficiency of the various discharge regimes (diffusion and volume recombination with either single or step-wise ionisation); (v) the EM E-field intensity under the electron cyclotron resonance (ECR) condition passes through a minimum, not a maximum, contrary to what is generally claimed; (vi) similarity laws, originally derived with DC discharges, are generalized to include RF and microwave discharges. For example, θ A /p as a function of pR (p is the gas pressure and R the discharge tube inner radius) replaces advantageously the widely used E/p versus pR similarity law since θ A is more easily measured than E 2 and further it prevents considering the latter as an external parameter, etc. The important EM power loss due to space-wave radiation in the immediate vicinity of the SW launching interstice has escaped the attention of those working with SWDs. This effect is documented experimentally, showing in addition that it can be significantly reduced by using a cylindrical conducting enclosure, coaxial with the discharge tube, having a small enough radius such that it acts as a circular waveguide at cut-off. A survey limited to underlining specific properties and innovative features of SWDs other than plasma columns is conducted, which include planar SWDs and microwave discharges of the torch type sustained at atmospheric pressure, for instance, with the TIA and TIAGO E-field applicators: it is shown that their flame actually results from an SWD.

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Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

Section: Conditions On the Fr Product For Sustaining A Plasma Column ...mentioning

confidence: 99%

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Contribution of surface-wave (SW) sustained plasma columns to the modeling of RF and microwave discharges with new insight into some of their features. A survey of other types of SW discharges

Moisan¹,

Nowakowska²

2018

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

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“…Our recently developed surface wave-initiated microwave torch [30][31][32][33][34][35] can also be a source of low-temperature plasma. In this case, the plasma is produced by an electromagnetic wave that travels along the interface between the plasma and the dielectric [36].…”

Section: Introductionmentioning

confidence: 99%

“…In the microwave discharge, the plasma has a higher electron temperature than plasma obtained by the indirect and high-frequency discharge. Due to the high temperature of the electrons, there is also a higher dissociation and ionization degree, which is reflected in a wide range of uses of this type of discharge including wound healing [30][31][32][33], surface decontamination of fruits [34] or deposition of thin layers [35]. This paper focuses on the first use of this discharge in the yeast Candia glabrata as a model microorganism.…”

Section: Introductionmentioning

confidence: 99%

Impact of Microwave Plasma Torch on the Yeast Candida glabrata

et al. 2020

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Recently, various cold plasma sources have been tested for their bactericidal and fungicidal effects with respect to their application in medicine and agriculture. The purpose of this work is to study the effects of a 2.45 GHz microwave generated plasma torch on a model yeast example Candida glabrata. The microwave plasma was generated by a surfatron resonator, and pure argon at a constant flow rate of 5 Slm was used as a working gas. Thanks to a high number of active particles generated in low-temperature plasma, this type of plasma has become highly popular, especially thanks to its bactericidal effects. However, its antimycotic effects and mechanisms of fungal inactivation are still not fully understood. Therefore, this study focuses on the antifungal effects of the microwave discharge on Candida glabrata. The main focus is on the measurement and evaluation of changes in inactivation effects caused by varying initial concentration of Candida glabrata cells, applied microwave power and exposure time. The discharge was applied on freshly inoculated colonies of Candida glabrata spread on the agar plates and its inhibitory effects were observed in the form of inhibition zones formed after the subsequent cultivation.

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Theoretical parametric investigation of plasma sustained by traveling electromagnetic wave in coaxial configuration

Cited by 2 publications

References 10 publications

Contribution of surface-wave (SW) sustained plasma columns to the modeling of RF and microwave discharges with new insight into some of their features. A survey of other types of SW discharges

Contribution of surface-wave (SW) sustained plasma columns to the modeling of RF and microwave discharges with new insight into some of their features. A survey of other types of SW discharges

Impact of Microwave Plasma Torch on the Yeast Candida glabrata

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