Exponential decreasing nature of plasma density in a one dimensional slab by ambipolar diffusion

This program help to visualize the exponential decreasing nature of plasma density in a one dimensional slab by ambipolar diffusion. I have chosen the particular point at distance x = 0.01m from the slab to simulate the decay of density.


% This is a program to plot the decay of plasma by ambipolar diffusion in one dimensional slab:
clear all
close all

n_o = 1e12;          % initial density in m^-3
L = 0.024;           % length of edge from centre of the slab in m 
D = 0.4;             % ambipolar diffusion coeffecient in m^2/sec
T = (2*L/pi)^2/D;    % tau:mean time between collision

t = 0:.00002:.002;

x = .010;

n = n_o*exp(-(t./T)).*cos(pi*x./2/L);   % density distribution

comet(t,n),xlabel('t(time of decay)'),ylabel('n(density of plasma)'),
title('exponential decay of plasma dendity at position "x = .010m" of slab')