General Solution of a Fractional Diffusion-Advection Equation for Solar Cosmic-Ray Transport

In this effort we exactly solve the fractional diffusion-advection equation for solar cosmic-ray transport proposed in \cite{LE2014} and give its {\it general solution} in terms of hypergeometric distributions. Also, we regain all the results and approximations given in \cite{LE2014} as {\it particular cases} of our general solution.