A possible explanation of the variation of the scattering index parameter

The variation of the scattering index parameter () with galactic latitude and longitude is compared with the absorption measurements as well as electron density variations in the intersteller medium (ISM). We thus extend an earlier work (Okeke, 1981) by showing that the existence of a three-phase structure for the ISM could be responsible for the random variation of , which possibly is a good indicator of the nature of the ISM.