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% Cartoon of an electron passing through a bending magnet

% and the radiation it produces

 

clear; close all;

 

% Prompt user for speed of video

prompt = 'Slow (0) or fast(1) animation? [default = slow, 0]: ';

frRate = input(prompt);

if isempty(frRate)

    frRate = 30;

else

    frRate = 60;

end

 

figure('units','pixels','position',[0 0 1920 1080],'ToolBar','none');

vid = VideoWriter('BMradiation.mp4','MPEG-4');

vid.Quality = 100;

vid.FrameRate = frRate;

open(vid);

set(0,'defaultfigurecolor',[1 1 1]);

set(gca,'linewidth',7);

 

coneCol = [1.0 0.83 0];         % golden synchrotron radiation!

darkGrey = [0.4 0.4 0.4];       % north pole

lightGrey = [0.6 0.6 0.6];      % south pole

myBlue = [0.4 0.44 0.73];       % electron

 

LL = 10;

 

[x,y,z] = sphere; % Create sphere coordinates

er = 0.07; % radius of electron

 

% Create angular array of 30 degrees

phistep = pi/360;

phipos = 0:phistep:pi/6; % 0 - 30 degrees

phineg = pi/6:-phistep:0;

r1 = 8; % inner radius of BM

r2 = 8.8; % outer radius of BM

avr = (r1+r2)/2;

mTTh = 1.0; % z-value of top of top magnet. Use negative of this for bottom of bottom magnet

mTBh = 0.5; % z-value of bottom of top magnet. Use negative of this for top of bottom magnet

 

% Draw top magnet

 

% Coords of top surface of top magnet

mTTx1 = r1*sin(phipos); % x-coords of inner edge of top surface of top magnet

mTTx2 = r2*sin(phineg); % x-coords of outer edge of top surface of top magnet

mTTx = [mTTx1 mTTx2]; % x-coords of top surface of top magnet via concatenation

mTTy1 = r1*cos(phipos); % y-coords of inner edge of top surface of top magnet

mTTy2 = r2*cos(phineg); % y-coords of outer edge of top surface of top magnet

mTTy = [mTTy1 mTTy2]; % y-coords of top surface of top magnet via concatenation

mTTz = 0.0*mTTx + mTTh; % z-coords of top surface of top magnet

 

% Coords of inner curved surface of top magnet

mTIx1 = r1*sin(phipos); % x-coords of top edge of inner curved surface of top magnet

mTIx2 = r1*sin(phineg); % x-coords of bottom edge of inner curved surface of top magnet

mTIx = [mTIx1 mTIx2]; % x-coords of inner curved surface of top magnet via concatenation

mTIy1 = r1*cos(phipos); % y-coords of top edge of inner curved surface of top magnet

mTIy2 = r1*cos(phineg); % y-coords of bottom edge of inner curved surface of top magnet

mTIy = [mTIy1 mTIy2]; % y-coords of inner curved surface of top magnet via concatenation

mTIz1 = 0.0*mTIx1 + mTTh; % z-coords of top edge of inner curved surface of top magnet

mTIz2 = 0.0*mTIx1 + mTBh; % z-coords of bottom edge of inner curved surface of top magnet

mTIz = [mTIz1 mTIz2]; % z-coords of inner curved surface of top magnet

 

% Coords of end face of top magnet

lastp = size(mTTx1,2);

mTEx = [mTTx1(lastp) mTTx2(1) mTTx2(1) mTTx1(lastp)];

mTEy = [mTTy1(lastp) mTTy2(1) mTTy2(1) mTTy1(lastp)];

mTEz = [mTTh mTTh mTBh mTBh];

 

% Coords of path of electron

ePathxArc = avr*sin(phipos); % x-coords of arc

ePathxS1 = -avr/3:avr*phistep:0-avr*phistep; % x-coords of initial straight path

ePathxS2 = avr/2+avr*phistep*3^0.5/2:avr*phistep*3^0.5/2:avr*(0.5+3^0.5/6); % x-coords of final straight path

ePathx = [ePathxS1 ePathxArc ePathxS2];

ePathyArc = avr*cos(phipos); % y-coords of arc

ePathyS1 = avr+0.0*ePathxS1; % y-coords of initial straight path

ePathyS2 = avr*3^0.5/2-avr*phistep/2:-avr*phistep/2:avr*3^0.5/2-avr/6; % y-coords of final straight path

ePathy = [ePathyS1 ePathyArc ePathyS2];

ePathzArc = 0.0*sin(phipos);

ePathzS1 = 0.0*ePathxS1;

ePathzS2 = 0.0*ePathxS2;

ePathz = [ePathzS1 ePathzArc ePathzS2];

beamAngleArc = 0:pi/360:pi/6;

beamAngleS1 = 0.0*ePathxS1;

beamAngleS2 = pi/6+0.0*ePathxS1;

beamAngle = [beamAngleS1 beamAngleArc beamAngleS2];

 

% Create light cone

conecoord1 = 0:0.01:pi;     % coordinates of light cone schematic

conecoord2 = 0:0.02:2*pi;   % coordinates of light cone schematic

[conecoord1,conecoord2]=meshgrid(conecoord1,conecoord2);

 

zcoordcone1 = 0.25*(1 - sin(conecoord1)).*sin(conecoord1).*cos(conecoord2);

ycoordcone1 = 0.25*(1 - sin(conecoord1)).*sin(conecoord1).*sin(conecoord2);

xcoordcone1 = 7*abs(cos(conecoord1)).^2;

 

for i = 1:size(ePathx,2)

    hold off

    newplot

    hold on

    % Draw path of electron

    ePath = plot3(ePathx,ePathy,ePathz,'color',[0,0,0.7], 'LineWidth', 2.5);

    ePath.Color(4) = 0.5; % 50% opacity

    

    % Draw top magnet

    mTT = fill3(mTTx,mTTy,mTTz,darkGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    mTI = fill3(mTIx,mTIy,mTIz,darkGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    mTE = fill3(mTEx,mTEy,mTEz,darkGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    

    % Draw bottom magnet

    mBT = fill3(mTTx,mTTy,-mTTz+(mTTh-mTBh),lightGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    mBI = fill3(mTIx,mTIy,-mTIz,lightGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    mBE = fill3(mTEx,mTEy,-mTEz,lightGrey,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    

    elec = surf(ePathx(i)+x*er,ePathy(i)+y*er,ePathz(i)+z*er,'FaceColor',...

        myBlue,'LineStyle','none','FaceLighting','gouraud','DiffuseStrength',1);

    

    if (i>=size(ePathxS1,2)) && (i<=size(ePathx,2) - size(ePathxS2,2))

        lightCone = surf(xcoordcone1+ePathx(i),ycoordcone1+ePathy(i),zcoordcone1+ePathz(i),... 

            'FaceAlpha',0.5,'FaceColor',coneCol,'LineStyle','none','FaceLighting',... 

            'gouraud','DiffuseStrength',1);

        rotate(lightCone,[0 0 1],-beamAngle(i)*180/pi,[ePathx(i),ePathy(i),ePathz(i)]);

    end

    set(gca, 'Projection','perspective');

    set(gca,'View',[25,28]);

    lp = [-0.7 -0.5 0.5];

    light('Position',lp,'Style','infinite');

    axis equal

    axis off

    xlim([-LL/3.5 LL+1]);

    ylim([3.5 r2+0.1]);

    zlim([-1.1 1.1]);

    

    % Store the frame

    frame = getframe(gcf);

    writeVideo(vid,frame);

end

% End of phi-rotation loop

 

% Output the movie as an mpg file

close(vid);