• J P Singh

Articles written in Pramana – Journal of Physics

• Working group report: Quantum chromodynamics (QCD) and hadronic structure

We discuss potential problems in hadronic physics. Recent developments are reviewed and possible future studies in some interesting areas which are underway are highlighted.

• Optical emission from laser-produced chromium and magnesium plasma under the effect of two sequential laser pulses

Parametric study of optical emission from two successive laser pulses produced chromium and magnesium plasma is presented. The line emission from chromium and magnesium plasma showed an increase by more than six times for double laser pulse excitation than for single-pulse excitation. An optimum increase in emission intensity was noted for inter-pulse delay of ∼2–3 μs for all the elements. The experimental observations were qualitatively explained on the basis of absorption of second laser pulse in the pre-formed (by first laser) coronal plasma by inverse Bremsstrahlung process, which were found responsible for the excitation of more ions and atoms in the plasma. This process starts as the plasma scale length becomes greater than the laser wavelength. This study further indicated the suitability of this technique in the field of elemental analysis

• Perfect fluid Bianchi Type-I cosmological models with time varying 𝐺 and 𝛬

Bianchi Type-I cosmological models containing perfect fluid with time varying 𝐺 and 𝛬 have been presented. The solutions obtained represent an expansion scalar 𝜃 bearing a constant ratio to the anisotropy in the direction of space-like unit vector $\lambda^{i}$. Of the two models obtained, one has negative vacuum energy density, which decays numerically. In this model, we obtain $\Lambda \sim H^{2}$, $\Lambda \sim R_{44}/R$ and $\Lambda \sim T^{-2}$ (𝑇 is the cosmic time) which is in accordance with the main dynamical laws for the decay of 𝛬. The second model reduces to a static solution with repulsive gravity.

• # Pramana – Journal of Physics

Volume 96, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019