Plasma density determination

An approach to the indirect probing of inhomogeneous plane stratified plasmas is presented which, within numerical limitations, yields unique electron density profiles. It has been shown that the density profile and the reflected wave generated by a \delta - function incident electric field are uniquely related by a Fredholm integral equation. The integral equation is solved numerically by transforming it to a matrix equation. The values of the reflected wave at equally spaced time points determine the matrix elements. As the interval between the time points is decreased, the electron density obtained from the inversion of the matrix equation approaches the actual density. To illustrate the method, profiles are obtained for some plasmas whose density is constant or a decreasing function.