Heating of the interstellar gas by cosmic rays and warm transparent ionized plasma observed by pulsar dispersions

TL;DR

This paper analyzes the heating of interstellar gas by cosmic rays and observes warm ionized plasma through pulsar dispersion measures, revealing properties of different temperature regions in the galaxy.

Contribution

It provides a detailed analysis of interstellar plasma properties across temperature regimes using pulsar dispersion data, focusing on the warm ionized medium.

Findings

WIM plasma is transparent and observable via dispersion measurements.

Mass densities of WIM are comparable to dark matter densities.

Different plasma states are characterized by temperature-dependent spectroscopic effects.

Abstract

Electrons densities in different locations of our galaxy are obtained in pulsar astronomy by dividing the dispersion measure (DM) by the distance of the pulsar to Earth. The properties of the interstellar plasma are related to its heating. Following the present analysis DM measurements are obtained with different properties for different temperatures in three regions:1)For relatively low temperatures the state of molecular, atomic and ionized Hydrogen was analyzed by the interstellar medium (ISM) model with partially ionized plasma. In this region various spectroscopic effects are obtained. 2) For temperatures approximately above 20000 (K) the interstellar gas was found to be completely ionized medium and this plasma is defined as warm ionized medium (WIM) where this plasma is transparent. This property is obtained from solution of Saha equation in which the index of refraction is real, but the plasma can be observed by dispersion measurements.3)For very high temperatures defined as hot ionized matter (HIM), X-rays are obtained by the plasma. We concentrate in the work on the analysis of the WIM plasma. We calculate the mass densities of such plasma and compare it with dark matter densities which are found to be larger. But some factors which can reduce this difference are discussed,