function ydot=eq_2disc_comb0(t,y);
%Equation of 4 discs dynamo to describe both secular and 22-years variations with a "TOY" model.
%Volobuev, D. "Toy" dynamo to describe the long-term solar activity cycles. Solar Physics 238, 421-430 (2006)
%Example of MatLab 5.x-6.x command line call
%
%[T,Y] = ode45(@eq_2disc_comb0,.1:.1:60,[-2 -2 -5 0 .1 .1]);
%figure;plot(T,Y);legend('I_1','I_2','\omega','I','\Omega','\omega_0')
%figure;plot(T,Y(:,1).^2+Y(:,2).^2+Y(:,4).^2);title('magnetic energy')
%figure;plot(Y(:,1),Y(:,2));xlabel('poloidal field');ylabel('toroidal field')
mu=1;K=2; A=mu*(K^2-K^-2);F0=-11;%constants, see the paper, pp.423-424
dt11=1.6;dt=.2;%time scaling coefficients, p.427
%Equation 3, p.427
ydot(1)=dt11*(-mu*y(1)+y(3)*y(2));
ydot(2)=dt11*(-mu*y(2)+(y(3)-A)*y(1));
%1-disc dynamo with a "motor"
alpha=5;beta=4;k=0;lambda=1.2;%constants, see the paper,p.426
ydot(4)=dt*(y(4)*(y(5)-1)-beta*y(6));%
ydot(5)=dt*(alpha*(1-y(4)^2)-k*y(5));%
ydot(6)=dt*(y(4)-lambda*y(6));
%Equation for a frictional connection between discs
ydot(3)=dt11*(F0-y(1)*y(2)-ydot(5));%eps=dt11*ydot(5)
ydot=ydot(:);