9 research outputs found
Collisionless plasma expansion in the presence of a dipole magnetic field
The collisionless interaction of an expanding high-energy plasma cloud with a
magnetized background plasma in the presence of a dipole magnetic field is
examined in the framework of a 2D3V hybrid (kinetic ions and massless fluid
electrons) model. The retardation of the plasma cloud and the dynamics of the
perturbed electromagnetic fields and the background plasma are studied for high
Alfven-Mach numbers using the particle-in-cell method. It is shown that the
plasma cloud expands excluding the ambient magnetic field and the background
plasma to form a diamagnetic cavity which is accompanied by the generation of a
collisionless shock wave. The energy exchange between the plasma cloud and the
background plasma is also studied and qualitative agreement with the analytical
model suggested previously is obtained.Comment: 10 pages, 4 figure
Boosting the Power Generation in Wind and Hydro Power Production
When approaching a conventional wind turbine, the air flow is slowed down and widened. This results in a loss of turbine efficiency. In order to exploit wind or water flow power as effectively as possible, it was suggested that the turbine should be placed inside a shroud, which consists of 4 wing-shaped surfaces. Two internal air foils improve the turbine performance by speeding up the flow acting on the turbine blades, two external wings create a field of low pressure behind the turbine, thus, helping to draw more mass flow to the turbine and avoid the loss of efficiency due to flow deceleration. The system accumulates kinetic energy of the flow in a small volume where the smaller (and therefore, cheaper) turbine can be installed. A smaller system can be installed inside the bigger one, which would help to accumulate even more kinetic energy on the turbine. This method implies kinetic energy summation with local flow redistribution. Both experiments and CFD simulations demonstrate a significant increase in velocity and generated mechanical power in comparison to those for a bare turbine