Executive Summary : | The magnetohydrodynamic (MHD) waves and fluid instabilities play a significant role in the structure formation of gaseous clouds in the interstellar medium (ISM). The hydrodynamic instabilities are due to the non-equilibrium state of the plasma which draws energy from the medium for their development. These are mainly responsible for macroscopic changes in their initial states. In past decades, there has been great interest grown in this field due to its significance in star formation in molecular clouds, accretion disks, protostellar disks, dense stars, nebulae, core-collapse supernovae etc. Some of these instabilities of our interests are thermal instability, gravitational (Jeans) instability and magnetorotational instability (MRI) have unavoidable roles in various interesting phenomena in astrophysical and space plasmas. The instabilities are under investigation by many researchers in different plasma environments. Although, several works have been carried out still there are many gaps where we can work. From the literature review, it is found that much more work to be done for understanding the waves, instabilities and turbulent behaviour in the astrophysical plasmas. The recent observational data of the various astrophysical systems can be used to describe the significant role of these instabilities in such systems. In recent years, a good amount of work has been carried out to study the properties of galactic cosmic rays and their influence on the ISM. Cosmic rays (CRs) are the charged particles with kinetic energies (from eV to ZeV) ejected from galactic objects such as supernova remnants (SNRs) and accretion disks. The interaction of CRs with plasma in the ISM gives rise to many interesting features of waves and instabilities in astrophysical plasmas (Prajapati, MNRAS 510, 2127 (2022)). Although in the previous works, many authors have studied the effects of radiative functions, thermal conductivity, magnetic fields and uniform rotation. But, none of the authors has investigated the effects of CR-driven wave modes and instability to understand the structure formation in the ISM. The above work motivates further to investigate the effects of various parameters, such as non-ideal effects (Ohmic and Hall diffusion), charged dust grains, anisotropic CRs diffusion, differential rotation and pressure anisotropy on the CR-driven MHD waves and instabilities in plasmas. Therefore, the objective of the proposed research project is to study the interaction of galactic cosmic rays with plasmas and associated MHD waves and fluid instabilities for various plasma configurations. |