K. C. Swami

Effect of finite ion temperature on modulational instability of ion-acoustic waves

Abstract A nonlinear Schrodinger equation for ion-acoustic waves in a collision free plasma, consisting of warm ions and hot isothermal electrons is derived using the KBM method. It is found that for finite ion temperature these waves are modulationally unstable only in a range of wave numbers. As the ratio of ion to electron temperature increases, the range of the unstable region decreases and shifts towards small wave numbers.

Transition radiation by a charged particle moving across a plasma sheet

Expressions are derived for the transition radiation fields due to a charged particle passing across a dielectric layer surrounded by media of different dielectric constants. Transition radiation for a cold plasma sheet is discussed in detail and radiation patterns on both sides of the sheet are presented for different values of the particle velocity and the thickness of plasma sheet. The radiation patterns are found to depend sensitively on these parameters.

Energy loss by a charged particle moving in a hot collisional plasma

The rate of energy loss by a charged particle moving in a hot collisional plasma is determined by wave theory. Using BGK collision model, an explicit expression for the dielectric function is derived. The rate of energy loss of the test charge is calculated to second order terms in collisions and electron thermal velocity.

Enhancement in biological response of Ag-nano composite polymer membranes using plasma treatment for fabrication of efficient bio materials

Biomaterials are nonviable material used in medical devices, intended to interact with biological systems, which are becoming necessary for the development of artificial material for biological systems such as artificial skin diaphragm, valves for heart and kidney, lenses for eye etc. Polymers having novel properties like antibacterial, antimicrobial, high adhesion, blood compatibility and wettability are most suitable for synthesis of biomaterial, but all of these properties does not exist in any natural or artificial polymeric material. Nano particles and plasma treatment can offer these properties to the polymers. Hence a new nano-biomaterial has been developed by modifying the surface and chemical properties of Ag nanocomposite polymer membranes (NCPM) by Argon ion plasma treatment. These membranes were characterized using different techniques for surface and chemical modifications occurred. Bacterial adhesion and wettability were also tested for these membranes, to show direct use of this new class o...

Rate of energy loss by a charge moving in a turbulent plasma

The rate of energy loss by a charged particle moving in a turbulent plasma is considered using wave theory formalism, and the loss rate is calculated for the case of weak electrostatic turbulence.

Effect of turbulence on the rate of energy loss by a test charge moving in a plasma

Abstract The energy loss rate of a charge moving in a turbulent plasma is calculated using the dielectric formalism. It is found that the net effect of the turbulence is to decrease the energy loss rate of the test charge.

Excitations of wave modes and energy loss by a charged particle passing through a plasma sheet

Expressions are presented for the field components due to a charged particle passing across a dielectric layer surrounded by the media of different dielectric constants. The case of a cold plasma sheet is discussed in detail. The energy loss due to the space‐wave part of the transition radiation has been reported in a previous paper. In the present paper, the energy loss due to the excitation of surface wave modes is considered. For the large thickness, the energy is lost through the surface wave mode which propagates for frequencies less than ωp/√2. However, for thin sheets, two modes are excited in which the radial wave number depends upon the thickness of the plasma sheet. The power flow per unit angular frequency along the radial direction is calculated for both the thick and thin plasma sheet. The contribution of the particle velocity, the layer thickness, and the frequency on the power flow per unit frequency is investigated in detail.

Rate of energy loss by a charged particle moving in a plasma cylinder

Abstract The rate of energy loss by a charged particle moving with a relativistic velocity along the axis of a dielectric cylinder of infinite length surrounded by a medium of another dielectric constant has been calculated. The case of a cold plasma cylinder has been considered in detail in which the dielectric constant of the outer medium is taken to be infinite or unity.

Cerenkov radiation by a particle moving with a non-uniform velocity

Energy loss by a charged particle moving with non-uniform velocity in a uniform dielectric medium is investigated. Assuming constant deceleration, an expression is derived for radiation emitted in an arbitrary distance x, and the case of Cerenkov radiation is discussed in detail. Expressions are presented for energy radiated per unit frequency interval and for Cerenkov angle containing first-order terms in retardation.