Solar Type IIIb Radio Bursts as Tracers for Electron Density Fluctuations in the Corona

We present an estimation of the electron density modulation index ( δN_e/N_e ) for the first time using solar type IIIb radio burst observations. The mean value of δN_e/N_e is calculated to be ≈ 0.006±0.002 over the heliocentric distance range r ≈1.6 2.2 R_⊙ . The estimated δN_e/N_e shows a power law dependence on r with a power law index ≈ 0.31±0.10 . The wavenumber ( k ) spectrum for the electron density fluctuation (δN_e/N_e)^2 values shows a Kolmogorov-like behavior. Using δN_e/N_e and the Kolmogorov turbulence index, we estimated the amplitude of density turbulence [ C_n^2(r) ] in the aforementioned range of r .