A test particle study of the ionospheric source of plasma in the EarthÕs plasma sheet has been performed, in an effort to understand an apparent inconsistency between the results of forward and backward (in time) test particle calculations. Most if not all forward calculations of polar wind ion outflows result in energetic plasma sheet ion populations; yet most if not all backward trajectory ca...

From the regular hexagon of unit size remove circular holes of small radius ε > 0 centered at the vertices, obtaining a region Hε of area 3 √ 3 2 − πε2. For each pair (x, ω) ∈ Hε × [0, 2π] consider a point particle moving at unit speed on a linear trajectory with specular reflections when meeting the boundary. Denote by τhex ε (x, ω) the time it takes the particle to reach one of the holes. Thi...

This paper investigates the velocity and the trajectory of water particles under surface waves, which propagate at a constant water depth, using particle image velocimetry (PIV). The vector fields and vertical distributions of velocities are presented at several phases in one wave cycle. The third-order Stokes wave theory was employed to express the physical quantities. The PIV technique's abil...

Stainless steel particles (60 μm in mean diameter) cladded with an alumina shell (2 μm thick and manufactured by mechanofusion) were sprayed with an Ar-H2 (53-7 slm) d.c. plasma jet (I = 500 A, P = 28 kW, th = 56 %). Two main types of particles were collected in flight, as close as 50 mm downstream of the nozzle exit: particles with a steel core with pieces of alumina unevenly distributed at t...

Spin of a test particle is fundamental property that can affect its motion in gravitational field. In this work we consider the effect spin on deflection angle and lensing equatorial plane arbitrary stationary axisymmetric spacetimes. To do developed perturbative method be applied to spinning signals with asymptotic velocity takes into account finite distance source observer. The $\Delta\varphi...

Constrained trajectory optimization has been a critical component in the development of advanced guidance and control systems. An improperly planned reference can be main cause poor online performance. Due to existence various mission-related constraints, feasible solution space model may restricted relatively narrow corridor, thereby easily resulting local minimum or infeasible detection. In t...

Aiming at the sensitivity to initial value and long computation time spent on iteration and programming the reference trajectory in reentry trajectory optimization for hypersonic vehicles, we propose a trajectory programming algorithm, which is based on drag acceleration profile. First of all, models of motion in reentry process of vehicle are built and an independent variable is introduced for...