Time-resolved measurement of plasma parameters by means of triple probe

Qayyum, A.; Ahmad, Nafis; Ahmad, Shamim; Deeba, F.; Ali, Rizwan; Hussain, Shafqat

doi:10.1063/1.4838658

Cited by 38 publications

(25 citation statements)

References 23 publications

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“…The Langmuir Triple probe is a disseminated technique for the diagnosis of plasma, which can provide the electronic temperature, i.e., the average energy of the electrons [ 56 , 57 ]. Then, it is possible to correlate the average energy of the electrons with the energy of the chemical bond, estimating the functional groups generated superficially during the plasma treatments [ 58 , 59 , 60 , 61 ].…”

Section: Methodsmentioning

confidence: 99%

Study of High-Density Polyethylene (HDPE) Kinetics Modification Treated by Dielectric Barrier Discharge (DBD) Plasma

et al. 2020

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In this work, the plasma was used in the dielectric barrier discharge (DBD) technique for modifying the high-density polyethylene (HDPE) surface. The treatments were performed via argon or oxygen, for 10 min, at a frequency of 820 Hz, voltage of 20 kV, 2 mm distance between electrodes, and atmospheric pressure. The efficiency of the plasma was determined through the triple Langmuir probe to check if it had enough energy to promote chemical changes on the material surface. Physicochemical changes were diagnosed through surface characterization techniques such as contact angle, attenuated total reflection to Fourier transform infrared spectroscopy (ATR-FTIR), X-ray excited photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Plasma electronics temperature showed that it has enough energy to break or form chemical bonds on the material surface, impacting its wettability directly. The wettability test was performed before and after treatment through the sessile drop, using distilled water, glycerin, and dimethylformamide, to the profile of surface tensions by the Fowkes method, analyzing the contact angle variation. ATR-FTIR and XPS analyses showed that groups and bonds were altered or generated on the surface when compared with the untreated sample. The AFM showed a change in roughness, and this directly affected the increase of wettability.

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Section: Methodsmentioning

confidence: 99%

Study of High-Density Polyethylene (HDPE) Kinetics Modification Treated by Dielectric Barrier Discharge (DBD) Plasma

et al. 2020

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“…The plasma density and temperature were measured with a triple Langmuir probe [34,35]. It consisted of three identical probe tips made of a tungsten wire with a diameter 0.6 mm and length 4.5 mm inserted axially within the plasma jet at a distance of 4 cm.…”

Section: Methodsmentioning

confidence: 99%

“…The voltage V dif between the floating probe 2 # and the biased probe 1 # was measured with a differential voltage amplifier. The electron temperature is deduced from the following equation [35]:…”

Section: Methodsmentioning

confidence: 99%

A pulsed ‘plasma broom’ for dusting off surfaces on Mars

2017

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Dust is a challenge for the design and operation of equipment on the Martian surface, particularly for solar cells. An efficient and robust technique for removing dust and sand from surfaces immersed in CO 2 at low pressure is presented. The working principle is based on a pulsed plasma jet produced between two coaxial electrodes biased at voltages between 1 and 2 kV. A demonstration is presented using dust particles whose chemical composition mimic the Mars soil. An array of connected photovoltaic cells fully covered with dust and sand is exposed to the plasma jet. The cells open circuit voltage is monitored in real-time thus providing the means to measure the dust removal efficiency. A good cleaning efficiency is attained after a few shots in a geometry where the plasma jet is directed perpendicularly to the dusty surface. The main advantage of this approach lies in the opportunity to apply it directly at about 5 Torr, the pressure of the Martian environment. A numerical evaluation shows that the plasma drag force on a dust particle is orders of magnitude higher than its weight depending on plasma density and flow speed, hence validating the principles of this cleaning technique.

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“…The probe circuit used here for GLAST-III does not contain any compensation for stray capacitance of the cables due to its negligible effect on cut-off frequency for relativity high electron density and temperature of ECRH-assisted microwave plasma. However, the effect of stray capacitance on cut-off frequency can be reduced significantly in low density and temperature plasmas by using appropriate guarding circuit [13][14][15]. Moreover, probe head is shielded by cylindrical aluminium casing that provides protection against electromagnetic noise and also serves as reference electrode for probe measurements during microwave discharge.…”

Section: Probe Design and Constructionmentioning

confidence: 99%

“…The toroidal electrical field requirement for breakdown can & A. Qayyum abdul.qaui@yahoo.com be reduced significantly by adopting various pre-ionization schemes during startup phase [15][16][17]. ECRH-assisted current startup is a scheme for generating toroidal plasma currents in tokomaks [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Triple-probe Diagnostic Measurements in Plasma of GLAST Spherical Tokamak

Qayyum¹,

Ahmad²,

Khan³

et al. 2015

J Fusion Energ

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Triple-probe has been developed and operated successfully to characterize ECRH-assisted argon as well as hydrogen microwave plasmas in GLAST Spherical Tokamak. This technique enables to determine transient plasma parameters such as floating potential, electron temperature and electron number density in rapidly timevarying plasmas. An effective electron heating mechanism is applied to produce microwave plasma by injecting radiofrequency (RF) radiation at a frequency of 2.45 GHz in the presence of resonant toroidal magnetic field. Plasma parameters and corresponding fluctuations are measured as a function of time in different gas fill pressures for various applied magnetic fields. The results demonstrate the dependence of plasma parameters such as V f , T e , n e and their fluctuations on gas fill pressure during the pre-ionization phase of the GLAST operation. Plasma behavior is observed to be closely depending on the coupling of RF power during microwave discharge. Additionally, the hydrogen plasma shows pronounced fluctuations in comparison with argon plasma with some decrease in electron temperature and densities.

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Time-resolved measurement of plasma parameters by means of triple probe

Cited by 38 publications

References 23 publications

Study of High-Density Polyethylene (HDPE) Kinetics Modification Treated by Dielectric Barrier Discharge (DBD) Plasma

Study of High-Density Polyethylene (HDPE) Kinetics Modification Treated by Dielectric Barrier Discharge (DBD) Plasma

A pulsed ‘plasma broom’ for dusting off surfaces on Mars

Triple-probe Diagnostic Measurements in Plasma of GLAST Spherical Tokamak

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