mie_s12.m

计算mie散射过程中的散射幅度函数

function result = Mie_S12(m, x, u)

% Computation of Mie Scattering functions S1 and S2
% for complex refractive index m=m'+im", 
% size parameter x=k0*a, and u=cos(scattering angle),
% where k0=vacuum wave number, a=sphere radius;
% s. p. 111-114, Bohren and Huffman (1983) BEWI:TDD122
% C. M鋞zler, May 2002

nmax=round(2+x+4*x^(1/3));
ab=Mie_ab(m,x);
an=ab(1,:);
bn=ab(2,:);

pt=Mie_pt(u,nmax);
pin =pt(1,:);
tin =pt(2,:);

n=(1:nmax);
n2=(2*n+1)./(n.*(n+1));
pin=n2.*pin;
tin=n2.*tin;
S1=(an*pin'+bn*tin');
S2=(an*tin'+bn*pin');
    
result=[S1;S2];