Technically, there are two types of propulsion systems namely chemical and electric depending on the sources of the fuel. Electrostatic thrusters are used for launching small satellites in low earth orbit which are capable to provide thrust for long time intervals. These thrusters consume less fuel compared to chemical propulsion systems. Therefore for the cost reduction interests, space scientists are interested to develop thrusters based on electric propulsion technology. This chapter is intended to serve as a general overview of the technology of electric propulsion (EP) and its applications. Plasma based electric propulsion technology used for space missions with regard to the spacecraft station keeping, rephrasing and orbit topping applications. Typical thrusters have a lifespan of 10,000 h and produce thrust of 0.1–1 N. These devices have E→×B→ configurations which is used to confine electrons, increasing the electron residence time and allowing more ionization in the channel. Almost 2500 satellites have been launched into orbit till 2020. For example, the ESA SMART-1 mission (Small Mission for Advanced Research in Technology) used a Hall thruster to escape Earth orbit and reach the moon with a small satellite that weighed 367 kg. These satellites carrying small Hall thrusters for orbital corrections in space as thrust is needed to compensate for various ambient forces including atmospheric drag and radiation pressure. The chapter outlines the electric propulsion thruster systems and technologies and their shortcomings. Moreover, the current status of potential research to improve the electric propulsion systems for small satellite has been discussed.

The contributed chapter discuss the applications of terahertz radiations and its generation mechanism through laser plasma interactions. The methods of generation of terahertz radiations from plasma wake field acceleration, higher harmonic generation and the laser beat wave plasma frequency are reviewed. The nonlinear current density oscillate the plasma at beat wave frequency under the effect of ponderomotive force and excite the terahertz radiation at beat wave frequency. The current state of the arts of the methods of generation has been incorporated. The mathematical expression of ponderomotive force has been derived under the influence of gradient of laser fields. In additions, the future challenge and their overcomes are also been discussed.

The presence of plasma density gradient is one of the main sources of Rayleigh–Taylor instability (RTI). The Rayleigh–Taylor instability has application in meteorology to explain cloud formations and in astrophysics to explain finger formation. It has wide applications in the inertial confinement fusion to determine the yield of the reaction. The aim of the chapter is to discuss the current status of the research related to RTI. The current research related to RTI has been reviewed, and general dispersion relation has been derived under the thermal motion of electron. The perturbed densities of ions and electrons are determined using two fluid approach under the small amplitude of oscillations. The dispersion equation is derived with the help of Poisson’s equation and solved numerically to investigate the effect of various parameters on the growth rate and real frequency. It has been shown that the real frequency increases with plasma density gradient, electron temperature and the wavenumber, but magnetic field has opposite effect on it. On the other hand, the growth rate of instability increases with magnetic field and density gradient, but it decreases with electron temperature and wave number.

Hall thrusters are frequently used by geostationary satellites and long range mission from Earth to Moon. Hall thruster has higher fuel efficiency, less fuel consumption, therefore less propellant storage is required on-board. The stream of electrons are used from the virtual cathode to neutralize the outer surface of the Hall thruster to overcome the charging related problems. This electron beam alter the density of the plasma inside the Hall thruster channel. It affects the oscillations of plasma and triggers the instability called as electron beam instability. In this paper, we use magnetohydrodynamics theory to obtain the modified dispersion relation under the presence of electron beam with the help of the Poissons equation. We obtain dispersion relation as polynomial of the order of five under the various parameters. The real part of the root give phase velocity of the wave and the imaginary part give growth rate of the instability. The growth rate and the real frequency depend on the various parameters like magnetic field, density of electron, ion and electron beam, mass of the electron, ion and electron beam, initial velocity. The density and velocity of the electron beam affect the growth rate and real frequency of the wave. Therefore the electron beam play important role to control the growth rate and phase velocity of the wave. The effect of various parameters on the growth rate and phase velocity are investigated.

This work investigates the effect of precipitating agents sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH) on the structural and magnetic properties of cobalt ferrite nanoparticles. The co-precipitation method was used to synthesize cobalt ferrite nanoparticles (S1 and S2). The synthesized nanoparticles were characterized by techniques such as x-ray diffraction (XRD) and scanning electron microscopy (SEM) and using a vibrating sample magnetometer at temperatures of 10 and 300 K. XRD results confirm the formation of cobalt ferrite nanoparticles. SEM images revealed the formation of round-shaped particles with a diameter range of 10–20 nm. Crystallite size, saturation magnetization, coercivity, squareness ratio, and anisotropy constant depend on the precipitating agents. The values of saturation magnetization for S1 are 23.6 and 32.6 emu/g whereas those for S2 are 27.4 and 41.2 emu/g at 10 and 300 K, respectively. These nanoparticles can be explored for applications in the fields of magnetism and biomedical science.