International Journal of Physics | Vol. 10, No. 6, June 2019 | pp. 41–48
DOI: 10.46882/2019/IJP/000110
Research Article
Title: Fluid Inflow Velocity Mapping and Reconnection Dynamics in Solar Prominence Ejections
Names of Authors: G. R. Davies¹, O. K. Semenov²
Authors’ Affiliations: ¹School of Physics and Astronomy, University of St Andrews, St Andrews, UK; ²Institute for Solid State Physics, Russian Academy of Sciences, Moscow, Russia
Abstract: Magnetic reconnection is the primary magnetohydrodynamic driver behind explosive energy release events in the solar atmosphere, accelerating the fast solar wind and initiating massive prominence ejections. This paper evaluates fluid inflow velocities and maps magnetic reconnection rates within an eruptive active loop using high-resolution data from satellite ultraviolet spectroscopic imagers. We tracked the Doppler profiles and spatial intensity variations of the C IV and Fe XII spectral emission lines to isolate magnetic topology changes under dense plasma constraints. The empirical measurements reveal systematic plasma inflows moving at 14.8 km/s, while directed outflows reach high velocities of 215.0 km/s along the magnetic separator lines. Based on these transport indicators, the local dimensionless reconnection rate was calculated to range between 0.04 and 0.07. These numbers track fast reconnection limits predicted by generalized Sweet-Parker equations adjusted for Hall currents and local plasmoid instabilities. Spectroscopic line-broadening diagnostics indicate localized turbulent temperatures peaking at 5.2 MK within the diffusion current sheet boundary, confirming strong viscous dissipation fields. These spectroscopic results provide robust observational constraints for calibration routines in coronal magnetohydrodynamics.
Keywords: Solar atmosphere; magnetic reconnection; prominence ejection; ultraviolet spectroscopy; plasma velocity; magnetohydrodynamics
Manuscript Timeline: Received: March 02, 2019; Revised: April 14, 2019; Accepted: May 02, 2019; Published: June 18, 2019
CN: Davies, G. R., & Semenov, O. K. (2019). Fluid Inflow Velocity Mapping and Reconnection Dynamics in Solar Prominence Ejections. International Journal of Physics, 10(6), 41–48.
International Journal of Physics | Vol. 10, No. 5, May 2019 | pp. 33–40
DOI: 10.46882/2019/IJP/000109
Research Article
Title: Quantum Efficiency Enhancement in Polymer Solar Cells via Localized Surface Plasmon Resonance of Copper Nanocubes
Names of Authors: H. K. Tanaka¹, M. G. Richter²
Authors’ Affiliations: ¹Department of Quantum Engineering, Nagoya University, Nagoya, Japan; ²Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
Abstract: Low absorption cross-sections within ultra-thin active layers limit the conversion efficiencies of organic and polymer thin-film photovoltaic systems. This study implements an approach to enhance the internal quantum efficiency of bulk-heterojunction polymer solar cells by incorporating synthesized copper nanocubes into the hole transport buffer layer. The solar devices were fabricated with an inverted architecture containing indium tin oxide, a metal oxide electron transport layer, and a blend active core. We adjusted the edge lengths of the copper nanocubes from 30.0 nm to 70.0 nm to align the localized surface plasmon resonance bands with the polymer absorption minima. Experimental UV-vis spectrophotometry demonstrates a significant 38.0% increase in optical absorption within the 500.0 nm to 650.0 nm spectrum when 50.0 nm nanocubes are integrated. Under simulated standard solar illumination (AM 1.5G, 100.0 mW/cm²), the optimized plasmonic polymer cell yielded a short-circuit current density of 12.15 mA/cm² and an open-circuit voltage of 0.64 V. This resulted in a maximum power conversion efficiency of 5.45%, representing a 30.0% boost over the control cell. Finite-difference time-domain simulations confirm that near-field electromagnetic field concentration and forward scattering drive this performance enhancement.
Keywords: Polymer photovoltaics; copper nanocubes; surface plasmon resonance; light harvesting; power conversion efficiency; finite-difference time-domain
Manuscript Timeline: Received: February 11, 2019; Revised: March 24, 2019; Accepted: April 10, 2019; Published: May 15, 2019
Citation: Tanaka, H. K., & Richter, M. G. (2019). Quantum Efficiency Enhancement in Polymer Solar Cells via Localized Surface Plasmon Resonance of Copper Nanocubes. International Journal of Physics, 10(5), 33–40.
International Journal of Physics | Vol. 10, No. 4, April 2019 | pp. 25–32
DOI: 10.46882/2019/IJP/000108
Research Article
Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering across Silicon-Diamond Heterojunctions
Names of Authors: D. W. Meyer¹, H. L. Mueller²
Authors’ Affiliations: ¹Institute of Physics, Karlsruher Institut für Technologie, Karlsruhe, Germany; ²Institut für Kernphysik, Karlsruher Institut für Technologie, Karlsruhe, Germany
Abstract: Dissipating intense localized heat across structural material boundaries is a significant challenge in modern wide-bandgap high-frequency nanoelectronics and high-power radar modules. This paper utilizes molecular dynamics simulations to quantify thermal dispersion metrics and track acoustic phonon wavepacket scattering at mismatched silicon-diamond (Si-C) heterojunctions. We constructed atomistic models using the optimized Tersoff empirical potentials, incorporating varying concentrations of interfacial dislocation defects and interfacial chemical grading configurations. Longitudinal and transverse acoustic phonon wavepackets were generated with narrow frequency spreads centered between 3.0 THz and 12.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 6.5 THz) undergo strong diffuse scattering at the rough interface, dropping the transmission coefficient from 0.72 down to 0.14. This transport degradation is driven by severe acoustic impedance mismatch and localized interface vibrational modes. The overall interfacial thermal conductance was calculated to decrease by 48.0% when the interface defect density scaled from 1.0% to 5.0% at 300.0 K. These molecular dynamics calculations clarify the atomic-scale paths limiting heat carrier propagation, helping engineers design targeted thermal management interfaces for high-power electronics.
Keywords: Thermal conductance; phonon wavepacket; molecular dynamics; interface defects; silicon-diamond; nanoelectronics
Manuscript Timeline: Received: January 08, 2019; Revised: February 17, 2019; Accepted: March 09, 2019; Published: April 10, 2019
Citation: Meyer, D. W., & Mueller, H. L. (2019). Thermal Dispersion Metrics and Phonon Wavepacket Scattering across Silicon-Diamond Heterojunctions. International Journal of Physics, 10(4), 25–32.
International Journal of Physics | Vol. 10, No. 3, March 2019 | pp. 17–24
DOI: 10.46882/2019/IJP/000107
Research Article
Title: Relativistic Hydrodynamic Simulations of Directed Flow Fluctuations in Asymmetric Carbon-Gold Collisions
Names of Authors: S. C. O’Brien¹, A. M. El-Chemali²
Authors’ Affiliations: ¹School of Physics, University College Dublin, Dublin, Ireland; ²Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon
Abstract: High-energy asymmetric nuclear collisions provide a unique experimental platform to probe the initial-state spatial geometry fluctuations required to form a brief droplet of quark-gluon plasma. This study presents a relativistic hydrodynamic simulation framework to model particle production cascades and evaluate directed flow fluctuations in carbon-gold (C-Au) collisions at a center-of-mass energy of 200.0 GeV per nucleon pair. We utilized a 3+1 dimensional viscous hydrodynamic code coupled with a statistical hadronization module to calculate final-state transverse momentum spectra. The initial energy density distributions were generated via a Monte Carlo Glauber model to track sub-nucleon scale configurations. The numerical simulations show that expanding fireballs develop a substantial radial flow profile, shifting the mean transverse momentum of protons up to 1.12 GeV/c in central events. The calculated directed flow coefficient (v1) displays a strong mass-ordering signature, which matches experimental tracking data from specialized heavy-ion detectors within a tight ±5.5% margin. This agreement implies that small-scale asymmetric nuclear interaction zones can briefly sustain fluid-like collective expansion profiles. These findings clarify the boundary constraints of fluid behavior in subatomic physics.
Keywords: Relativistic hydrodynamics; quark-gluon plasma; directed flow; asymmetric collisions; Glauber model; statistical hadronization
Manuscript Timeline: Received: December 14, 2018; Revised: January 20, 2019; Accepted: February 08, 2019; Published: March 11, 2019
Citation: O’Brien, S. C., & El-Chemali, A. M. (2019). Relativistic Hydrodynamic Simulations of Directed Flow Fluctuations in Asymmetric Carbon-Gold Collisions. International Journal of Physics, 10(3), 17–24.
International Journal of Physics | Vol. 10, No. 2, February 2019 | pp. 9–16
DOI: 10.46882/2019/IJP/000106
Research Article
Title: Kinetic Modelling of Electron Swarm Parameters and Fragmentation Pathways in Methane-Oxygen Discharges
Names of Authors: D. L. Santos¹, T. H. Nguyen²
Authors’ Affiliations: ¹Department of Physics, University of Coimbra, Coimbra, Portugal; ²Department of Physics, Vietnam National University, Hanoi, Vietnam
Abstract: Methane-oxygen (CH4-O2) gas discharges are widely deployed in material processing and chemical engineering sectors for diamond thin-film synthesis, surface activation, and greenhouse gas conversion. This paper develops a self-consistent kinetic model to evaluate electron swarm parameters and calculate molecular fragmentation pathways in low-pressure methane-oxygen mixtures. We solved the electron Boltzmann equation using a multi-term spherical harmonic expansion framework across a wide reduced electric field range (E/N) from 10.0 Td to 500.0 Td. The cross-section dataset accounted for elastic momentum transfer, rotational transitions, vibrational excitation states, dissociative attachment, and direct impact ionization processes. Our modeling results show that adding small fractions of oxygen (from 5.0% to 20.0% by volume) significantly distorts the high-energy tail of the electron distribution function. At E/N = 80.0 Td, the total methyl radical (CH3) production rate coefficient increases by over an order of magnitude due to efficient energy channeling into the primary vibrational thresholds of methane. The calculated electron drift velocities match independent swarm experimental measurements within a ±5.0% variance index. These kinetic parameters provide critical baseline inputs for optimizing commercial chemical vapor deposition reactors.
Keywords: Methane plasmas; Boltzmann equation; electron transport; fragmentation pathways; chemical vapor deposition; cross-section
Manuscript Timeline: Received: November 05, 2018; Revised: December 18, 2018; Accepted: January 11, 2019; Published: February 12, 2019
Citation: Santos, D. L., & Nguyen, T. H. (2019). Kinetic Modelling of Electron Swarm Parameters and Fragmentation Pathways in Methane-Oxygen Discharges. International Journal of Physics, 10(2), 9–16.
International Journal of Physics | Vol. 10, No. 1, January 2019 | pp. 1–8
DOI: 10.46882/2019/IJP/000105
Research Article
Title: Topological Valley States and Spin-Polarized Edge Transport in Fluorinated Tin Film Honeycomb Lattices
Names of Authors: J. W. Park¹, A. L. Silva²
Authors’ Affiliations: ¹Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea; ²Institute of Physics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Abstract: Valleytronics provides an alternative pathway for low-power electronic hardware architectures by leveraging the valley degree of freedom to lock charge transport. This study models topological valley states and characterises spin-polarized edge transport in two-dimensional honeycombed lattices of fluorinated tin (stanene) films. We executed electronic band calculations using the relativistic tight-binding method across the hexagonal Brillouin zone. The combination of structural inversion asymmetry and strong intrinsic spin-orbit coupling breaks the valley degeneracy, opening a wide topological bulk bandgap of 0.24 eV. The system exhibits a non-zero valley Chern number of Cv = +1, which confirms non-trivial topological valley properties. To evaluate transport robustness, we simulated electron wavepacket propagation past point vacancies and sharp 60-degree boundary folds. The valley-polarized edge mode bypassed these structural obstacles with a high transmission efficiency of 99.6% ± 0.2%, demonstrating an absence of backscattering due to valley-contrast conservation rules. These findings provide solid engineering guidelines for building backscattering-immune valley-filter switches, quantum pathways, and integrated low-dissipation logic networks.
Keywords: Valleytronics; topological insulators; spin-orbit coupling; tight-binding method; edge states; stanene films
Manuscript Timeline: Received: October 12, 2018; Revised: November 27, 2018; Accepted: December 15, 2018; Published: January 14, 2019
Citation: Park, J. W., & Silva, A. L. (2019). Topological Valley States and Spin-Polarized Edge Transport in Fluorinated Tin Film Honeycomb Lattices. International Journal of Physics, 10(1), 1–8.