We present multi-wavelength scatter broadening observations of 47 pulsars , made with the Giant Metre-wave Radio Telescope ( GMRT ) , Ooty Radio Telescope ( ORT ) and Long Wavelength Array ( LWA ) .
The GMRT observations have been made in the phased array mode at 148 , 234 , and 610 MHz and the ORT observations at 327 MHz .
The LWA data sets have been obtained from the LWA pulsar data archive .
The broadening of each pulsar as a function of observing frequency provides the frequency scaling index , \alpha .
The estimations of \alpha have been obtained for 39 pulsars , which include entirely new estimates for 31 pulsars .
This study increases the total sample of pulsars available with \alpha estimates by \sim 50 % .
The overall distribution of \alpha with the dispersion measure ( DM ) of pulsar shows interesting variations , which are consistent with the earlier studies .
However , for a given value of DM a range of \alpha values are observed , indicating the characteristic turbulence along each line of sight .
For each pulsar , the estimated level of turbulence , C ^ { 2 } _ { n _ { e } } , has also been compared with \alpha and DM .
Additionally , we compare the distribution of \alpha with the theoretically predicated model to infer the general characteristics of the ionized interstellar medium ( ISM ) .
Nearly 65 % of the pulsars show a flatter index ( i.e. , \alpha < 4.4 ) than that is expected from the Kolmogorov turbulence model .
Moreover , the group of pulsars having flatter index is typically associated with an enhanced value of C ^ { 2 } _ { n _ { e } } than those with steeper index .