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

We present an estimation of the electron density modulation index ( $\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ ) for the first time using solar type IIIb radio burst observations. The mean value of $\frac{\delta{N_{\mathrm {e}}}}{N_{\mathrm{e}}}$ is calculated to be ${\approx}\,0.006\pm0.002$ over the heliocentric distance range $r \approx1.6\,\mbox{--}\,2.2~\text{R}_{\odot}$ . The estimated $\frac {\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ shows a power law dependence on $r$ with a power law index ${\approx}\,0.31\pm0.10$ . The wavenumber ( $k$ ) spectrum for the electron density fluctuation $({\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm {e}}}})^{2}$ values shows a Kolmogorov-like behavior. Using $\frac{\delta{N_{\mathrm{e}}}}{N_{\mathrm{e}}}$ and the Kolmogorov turbulence index, we estimated the amplitude of density turbulence [ $C_{n}^{2}{(r)}$ ] in the aforementioned range of $r$ . [ABSTRACT FROM AUTHOR]