arXiv subjects

Satyananda Kar

Publications and source records attributed to Satyananda Kar.

11 recordsLinked to original sources

arXiv2026

Potential of Atmospheric Pressure Thermal Plasma Technology towards Waste Processing: A Comprehensive Review

The enhancement of living standards has significantly contributed to the rapid growth of urban populations, resulting in a substantial increase in municipal solid waste (MSW) generation. This trend underscores the critical need for sustainable, environmentally friendly, cost-effective, and highly efficient waste management solutions. This study highlights the pressing necessity for effective MSW management and examines plasma pyrolysis/gasification as an emerging technology to address this challenge. The article provides a detailed analysis of thermal plasma generation techniques employing diverse power sources, including direct current, alternating current, radiofrequency inductively coupled, and microwave-based systems. A comparative evaluation of various plasma torch designs is conducted, emphasizing their applicability in waste-to-energy and waste treatment processes. A comprehensive overview of the treatment of a broad spectrum of waste materials, such as MSW, sewage sludge, coal, wood, plastics, tyres, and rubber, using thermal arc plasma technology is presented. The process predominantly converts waste into a combustible gas (syngas) with a calorific value ranging from 5 to 15 MJ/Nm3 and produces vitrified slag or ash as a by-product. The findings suggest that thermal plasma pyrolysis/gasification offers a promising approach to waste management, facilitating energy generation and material recovery while addressing the challenges of increasing MSW generation.

physics.plasm-ph↗

arXiv2026

Development and Characterization of a Microwave Atmospheric Pressure Plasma Jet

Over the past decade, atmospheric pressure discharges in the microwave frequency range have gained significant attention due to their promising applications in material processing, CO2 dissociation, waste management, hydrogen production, water treatment, and more. This study presents the development and characterization of a waveguide-based microwave atmospheric pressure plasma jet (MW-APPJs), focusing on its design, diagnostics, and operational parameters. The setup incorporates a microwave power source, microwave waveguide networks, including the applicator section, and diagnostic tools for measuring plasma properties. Optical emission spectroscopy (OES) is employed to analyze the reactive species and determine plasma parameters which include electron excitation temperature (Texc) and electron number density (ne). The characterization highlights the influence of spatial and temporal gradients, gas flow rates, and power input on plasma behaviour. From OES, the Texc and ne variations were against the power increment. The thermocouple variations are also plotted with power.

physics.plasm-ph↗

arXiv2026

Gas Flow Rate Influence on Gas Temperature Regulation in a Reinforced Radio-Frequency Cross-Field Atmospheric Plasma Jet

This study investigates the effect of gas flow rate on the gas temperature and discharge characteristics of a reinforced radio frequency cross-field atmospheric pressure plasma jet (APPJ) with an additional floating electrode. The plasma jet length, electron excitation temperature, electron density, and reactivity were enhanced by introducing copper floating electrodes of varying widths. However, this enhancement was accompanied by an undesired rise in gas temperature, limiting the plasma's application for heat- sensitive materials. To control this temperature rise, the gas flow rate varied from 1.5 to 9 lpm, showing a significant reduction in gas temperature from 438 K to 402 K as the flow rate increased, particularly at higher input powers. The study reveals that while an increase in gas flow rate initially improves ionization and reactivity by increasing electron excitation temperature and density, the insufficient input power for ionization at higher flow rates causes a decline in these parameters due to reduced ionization efficiency. Further optimization was achieved by increasing input power, which allowed better utilization of neutral atoms and improved plasma reactivity even at higher flow rates. The findings highlight the importance of tuning both gas flow rate and input power to maintain optimal plasma performance for various applications, particularly where controlled gas temperature and high reactivity are essential.

physics.plasm-ph↗

arXiv2026

Enhanced Target Interaction Area of Helical Plasma Plumes in a Pulsed RF Atmospheric Plasma Jet

Helical plasma plumes generated in pulsed radiofrequency atmospheric pressure plasma jets exhibit unique flow dynamics arising from the coupling between Kelvin-Helmholtz instabilities and baroclinic torque. While the fundamental mechanism responsible for helical plume formation has been established, the implications of this morphology for plasma-target interaction remain largely unexplored. In this study, we experimentally investigate the interaction area of helical plasma plumes with different target configurations and compare it with the conventional conical plume produced under continuous RF excitation. High-speed imaging reveals that the helical plume significantly enlarges the effective plasma-target interaction region due to its rotating trajectory and enhanced air entrainment. The effect of different target materials and boundary conditions, including dielectric surfaces and metal-backed substrates, is systematically examined. The results demonstrate that helical plumes provide superior surface coverage, improved spatial distribution of reactive species, and enhanced plasma-surface coupling. These findings highlight the advantages of helical plasma jets for applications requiring large-area plasma treatment, including plasma medicine, surface modification, and plasma-liquid interactions.

physics.plasm-ph↗

arXiv2022

Influence of pulse modulation frequency on helium RF atmospheric pressure plasma jet characteristics

This work investigates the influence of pulse modulation frequency ranging from 50 Hz- 10 kHz on the helium RF atmospheric pressure plasma jet's fundamental characteristics. The impact of modulation frequency on plasma jet discharge behavior, geometrical variation, reactive species emission, and plasma parameters (gas temperature Tg, electron excitation temperature Texc, and electron density (ne) are studied using various diagnostics such as optical imaging, emission spectra, and thermal diagnostics. From the experiments, it is observed that operating the plasma jet at low pulse modulation frequencies (around 50 Hz) provides enhanced plasma dimensions, higher electron densities and greater optical emission from reactive species (viz., He I, O, OH, N2+, etc.) as compared to the higher modulation frequencies. Besides the low power consumption, the three times less gas temperature of the modulated plasma jet than the continuous wave mode makes it more advantageous for the applications. Moreover, the influence of duty cycle (D) and applied RF power (P) on the plasma jet characteristics are also discussed. It is found that 10- 40% duty cycle operation provides the most favorable attributes. More importantly, the concern of shorter plasma length in RF plasma jets is overcome by operating at 10- 20% duty cycle with increased applied power. This work thoroughly characterizes helium atmospheric pressure RF plasma jet with a wide range of pulse mode operating parameters, which could help select appropriate operating conditions for various industrial and biomedical applications.

physics.plasm-ph↗

arXiv2022

Excitation of helical shape argon atmospheric pressure plasma jet using RF pulse modulation

The article reports the excitation of a helical argon atmospheric pressure plasma jet using a pulse modulated 13.56 MHz radiofrequency (RF) power source. This helical structure is observed in open ambient air which is far different from the conventional conical shape. This helical structure originates due to the periodic pressure variation in the discharge region caused by pulse modulated RF (2 kHz modulation frequency (fp)) and propagates downstream into the ambient air. The geometrical characteristics of the observed structure are explored using optical imaging. Moreover, the influence of various input parameters viz., duty cycle (D), gas flow rate (Q), and RF power (P) of the modulated pulse on the formation of helical structure are studied. These helical structures have an implication on the plasma jet chemical features (enhancement of reactive oxygen and nitrogen species (RONS)) as these are involved in increase in air entrainment into the ionization region desired for various plasma applications.

physics.plasm-ph↗

arXiv2022

A Joint Calibration Technique for Improving Measurement Accuracy of Voltage and Current Probes During Synchronous Operation for RF Based Plasma Devices

This paper presents a joint calibration scheme for voltage (V) and current (I) probes that helps resolve accurately voltage-current phase differences even when the difference is very close to $90^{\circ}$. The latter has been a major issue with V-I probes when used with miniature RF plasma devices like the atmospheric pressure plasma jet (APPJ). Since the impedance of such miniature devices is predominantly capacitive, the phase difference between the voltage and current signals is very nearly $90^{\circ}$. It turns out, however, that when V-I probes are used with such devices without joint calibration, these frequently yield phase shifts over $90^{\circ}$. Also, since power absorption is proportional to the resistive part of the impedance it becomes very sensitive to the phase difference when it is close to $\approx90^{\circ}$. Thus, it is important to be able to resolve the phases accurately. Post-calibration, V-I probes would be indispensable for the electrical characterization of APPJs for determining average RF power $P_{av}$, plasma impedance $Z_p$, etc.Typical post-calibration V-I data yields, $Zp \approx 93.6 - j 1139 Ω (81.5 - j 1173 Ω)$ at $P_{av} \approx 9.8 W$ $(\approx7.7 W)$ for helium (argon) gas.

physics.plasm-ph↗

arXiv2022

Development and optimization of low power non-thermal plasma jet operational parameters for treating dyes and emerging contaminants

Emerging contaminants (ECs) have come out as the latest class of environmental contaminants, which are highly recalcitrant and toxic in nature. Currently, no suitable rectification methods are available against the ECs, resulting in a continuous increase in their concentration. Non-thermal plasma, as an advanced oxidation process, has been emerging as a promising technology against the ECs treatment. In the present work, a detailed experimental study is carried out to evaluate the efficacy of a non-thermal plasma jet with two dyes, Rhodamine B and Methylene Blue, as model contaminants. The plasma jet provided a complete dye decoloration in 30 min with an applied voltage of 6.5 kV. .OH, having the highest oxidation potential, acts as the main reactive species, which with direct action on contaminants also acts indirectly by getting converted into H2O2 and O3. Further, the effect of critical operational parameters viz., sample pH, applied voltage (4.5-6.5 kV), conductivity (5-20 mScm-1), and sample distance on plasma treatment efficacy was also examined. Out of all the assessed parameters, the applied voltage and sample conductivity was found to be the most significant operating parameter. A high voltage and low conductivity were found to favor the dye decoloration, while the pH effect was not that significant. To understand the influence of plasma discharge gas on treatment efficacy, all the experiments are conducted with Argon and Helium gases under the fixed geometrical configuration. Both the gases provided a similar dye decoloration efficiency. The DBD plasma system with complete dye removal also rendered maximum mineralization of 73 % for Rd. B, and 60 % for Met. Blue. Finally, the system's efficiency against the actual ECs (four pharmaceutical compounds, viz., metformin, atenolol, acetaminophen, and ranitidine) and microbial contaminant (Escherichia coli) was also tested.

physics.plasm-ph↗

arXiv2015

Temporal behavior of microwave sheath-voltage combination plasma

Microwave sheath-Voltage combination Plasma (MVP) is a high density plasma source and can be used as a suitable plasma processing device (e.g., ionized physical vapor deposition). In the present report, the temporal behavior of an argon MVP sustained along a direct-current biased Ti rod is investigated. Two plasma modes are observed, one is an "oxidized state" (OS) at the early time of the microwave plasma and the other is "ionized sputter state" (ISS) at the later times. Transition of the plasma from OS to ISS, results a prominent change in the visible color of the plasma, resulting from a significant increase in the plasma density, as measured by a Langmuir probe. In the OS, plasma is dominated by Ar ions and the density is order 10^11 cm^-3. In the ISS, metal ions from the Ti rod contribute significantly to the ion composition and higher density plasma (10^12 cm^-3) is produced. Nearly uniform high density plasma along the length of the Ti rod is produced at very low input microwave powers (around 30 W). Optical emission spectroscopy measurements confirm the presence of sputtered Ti ions and Ti neutrals in the ISS.

physics.plasm-ph↗

arXiv2015

Transient evolution of solitary electron holes in low pressure laboratory plasma

Solitary electrons holes (SEHs) are localized electrostatic positive potential structures in collisionless plasmas. These are vortex-like structures in the electron phase space. Its existence is cause of distortion of the electron distribution in the resonant region. These are explained theoretically first time by Schamel et.al [Phys. Scr. 20, 336 (1979) and Phys. Plasmas 19, 020501 (2012)]. Propagating solitary electron holes can also be formed in a laboratory plasma when a fast rising high positive voltage pulse is applied to a metallic electrode [Kar et. al., Phys. Plasmas 17, 102113 (2010)] immersed in a low pressure plasma. The temporal evolution of these structures can be studied by measuring the transient electron distribution function (EDF). In the present work, transient EDF is measured after formation of a solitary electron hole in nearly uniform, unmagnetized, and collisionless plasma for applied pulse width and, where and are applied pulse width and inverse of ion plasma frequency respectively. For both type of pulse widths, double hump like profile of transient EDF is observed, indicating that solitary electron hole exists in the system for time periods longer than the applied pulse duration. The beam (or free) electrons along with trapped (or bulk) electrons gives the solution of SEHs in the plasma. Without free or beam electrons, no SEHs exist. Transient EDF measurements reveal the existence and evolution of SEHs in the plasma. Measurements show that these structures live in system for longer time in the low pressure range. In high pressure cases, only single hump like transient EDF is observed i.e. only trapped or bulk electrons. In this situation, SEH does not exist in the plasma during evolution of plasma after the end of applied pulse.

physics.plasm-ph↗

arXiv2014

Microwave power coupling in a surface wave excited plasma

In recent decades, different types of plasma sources have been used for various types of plasma processing, such as, etching and thin film deposition. The critical parameter for effective plasma processing is high plasma density. One type of high density plasma source is Microwave sheath-Voltage combination Plasma (MVP). In the present investigation, a better design of MVP source is reported, in which over-dense plasma is generated for low input microwave powers. The results indicate that the length of plasma column increases significantly with increase in input microwave power.

physics.plasm-ph↗