scholarly journals Microscopic Effect on Filamentary Coherent Structure Dynamics in Boundary Layer Plasmas

Plasma ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Hiroki Hasegawa ◽  
Seiji Ishiguro
Keyword(s):  
Boundary Layer ◽  
Symmetry Breaking ◽  
Electron Temperature ◽  
Coherent Structure ◽  
Three Dimensional ◽  
Temperature Ratio ◽  
Pic Simulation ◽  
Particle In Cell ◽  
Plasma Filament ◽  
Potential Structure

This study has demonstrated kinetic behaviors on the plasma filament propagation with the three-dimensional (3D) Particle-in-Cell (PIC) simulation. When the ion-to-electron temperature ratio T i / T e is higher, the poloidal symmetry breaking in the filament propagation occurs. The poloidal symmetry breaking is thought to be induced by the unbalanced potential structure that arises from the effect of the gyro motion of plasma particles.

scholarly journals Thrust calculation of electric solar wind sail by particle-in-cell simulation

2016 ◽  
Vol 34 (9) ◽  
pp. 845-855 ◽  
Author(s):  
Kento Hoshi ◽  
Hirotsugu Kojima ◽  
Takanobu Muranaka ◽  
Hiroshi Yamakawa
Keyword(s):  
Solar Wind ◽  
Three Dimensional ◽  
Pic Simulation ◽  
Particle In Cell ◽  
Thrust Characteristics ◽  
Potential Structure ◽  
Cell Simulation ◽  
Simulation Results ◽  
Present Simulation ◽  
Electric Solar Wind Sail

Abstract. In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full three-dimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.

scholarly journals Use of Computer Experiments to Study the Current Collected by Cylindrical Langmuir Probes

2016 ◽  
Vol 3 (3) ◽  
pp. 105-109
Author(s):  
A. Tejero-del-Caz ◽  
J. M. Díaz-Cabrera ◽  
J. I. Fernández Palop ◽  
J. Ballesteros
Keyword(s):  
Electron Temperature ◽  
Langmuir Probe ◽  
Computer Experiments ◽  
Temperature Ratio ◽  
Langmuir Probes ◽  
Particle In Cell ◽  
Probe Radius ◽  
Cell Simulation ◽  
Cylindrical Langmuir Probe

A particle-in-cell simulation has been developed to study the behaviour of ions in the surroundings of a negatively biased cylindrical Langmuir probe. Here, we report our findings on the transition between radial and orbital behaviour observed by means of the aforementioned code. The influence of the ion to electron temperature ratio on the transition for different dimensionless probe radius is discussed. Two different behaviours have been found for small and large probe radii.

Design of W-Band Extended Interaction Output Cavity

2013 ◽  
Vol 427-429 ◽  
pp. 852-855
Author(s):  
Yong Zhong ◽  
Yong Wang
Keyword(s):  
Three Dimensional ◽  
Beam Current ◽  
Simulation Design ◽  
Pic Simulation ◽  
Output Cavity ◽  
Particle In Cell ◽  
Design And Optimization ◽  
Beam Voltage ◽  
W Band ◽  
Extended Interaction

In this paper, a novel extended interaction klystron output cavity is presented. With the help of a three-dimensional (3D) particle-in-cell (PIC) simulation, design and optimization geometry of the cavity is performed, which is composed of ladder loaded rectangular waveguide. In present work, the output continue wave (CW) power 724W is achieved, the efficiency and bandwidth reaches 7.5% and 1300MHz, which is operating at beam voltage and beam current is 16 kV and 0.6A , respectively.

scholarly journals Effective laser driven proton acceleration from near critical density hydrogen plasma

2016 ◽  
Vol 34 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Ashutosh Sharma ◽  
Alexander Andreev
Keyword(s):  
Laser Pulse ◽  
Hydrogen Plasma ◽  
Three Dimensional ◽  
Critical Density ◽  
High Energy ◽  
Intense Laser ◽  
Proton Density ◽  
Proton Acceleration ◽  
Pic Simulation ◽  
Particle In Cell

AbstractRecent advances in the production of high repetition, high power, and short laser pulse have enabled the generation of high-energy proton beam, required for technology and other medical applications. Here we demonstrate the effective laser driven proton acceleration from near-critical density hydrogen plasma by employing the short and intense laser pulse through three-dimensional (3D) particle-in-cell (PIC) simulation. The generation of strong magnetic field is demonstrated by numerical results and scaled with the plasma density and the electric field of laser. 3D PIC simulation results show the ring shaped proton density distribution where the protons are accelerated along the laser axis with fairly low divergence accompanied by off-axis beam of ring-like shape.

EXPERIMENTAL INVESTIGATION OF FLOW RESPONSE TO STATIONARY DISTURBANCE IN ROTATING-DISK FLOW

2019 ◽  
Vol XVI (2) ◽  
pp. 13-22
Author(s):  
Muhammad Ehtisham Siddiqui
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Careful Analysis ◽  
Laboratory Frame ◽  
Transition To Turbulence ◽  
Turbulent Regime ◽  
Mean Velocity ◽  
Layer Flow

Three-dimensional boundary-layer flow is well known for its abrupt and sharp transition from laminar to turbulent regime. The presented study is a first attempt to achieve the target of delaying the natural transition to turbulence. The behaviour of two different shaped and sized stationary disturbances (in the laboratory frame) on the rotating-disk boundary layer flow is investigated. These disturbances are placed at dimensionless radial location (Rf = 340) which lies within the convectively unstable zone over a rotating-disk. Mean velocity profiles were measured using constant-temperature hot-wire anemometry. By careful analysis of experimental data, the instability of these disturbance wakes and its estimated orientation within the boundary-layer were investigated.

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