磁偶极子的仿真

function hh=lforce3d(n,clr) % Lforce3D d2r = pi/180; r2d=1/d2r; tht=d2r*(0:5:360)'; phi=d2r*(0:ceil(180/n):180); hh=phi*r2d; A=50; r=A*sin(tht).^2; rho=r.*sin(tht); x=rho*cos(phi); y=rho*sin(phi); [nR,nC]=size(x); u=ones(1,nC); z=r.*cos(tht)*u; % Draw Line of Force h = figure; plot3(x,y,z,'r'); %,'LineWidth',1.0); hold on; axis equal % Draw The Earth's Spheroid [u,v,w]=sphere(25); surf(10*u,10*v,9*w); colormap('default'); camlight right; lighting phong; % shading interp % Add 3D arrow heads hold on; for iC=1:nC p1=[x(1:4:ceil(nR/2)-1,iC) y(1:4:ceil(nR/2)-1,iC) -z(1:4:ceil(nR/2)-1,iC)]; p2=[x(2:4:ceil(nR/2),iC) y(2:4:ceil(nR/2),iC) -z(2:4:ceil(nR/2),iC)]; % hn=arrow3(p1,p2,s,w,h,ip,alpha,beta) arrow3(p1,p2,clr,1.5,3); end % return for iC=1:nC p1=[x(ceil(nR/2):4:nR-1,iC) y(ceil(nR/2):4:nR-1,iC) z(ceil(nR/2):4:nR-1,iC)]; p2=[x(ceil(nR/2)+1:4:nR,iC) y(ceil(nR/2)+1:4:nR,iC) z(ceil(nR/2)+1:4:nR,iC)]; arrow3(p1,p2,clr,1.5,3); end title('Magnetic Field of A Dipole','FontSize',15); hold off; grid view(3); % cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc function hn=arrow3(p1,p2,s,w,h,ip,alpha,beta) % ARROW3 % ARROW3(P1,P2) will draw vector lines (2D/3D) from P1 to P2 with % arrowheads, where P1 and P2 can be either nx2 matrices (for 2D), % or nx3 matrices (for 3D). % % ARROW3(P1,P2,S,W,H,IP,ALPHA,BETA) can be used to specify properties % of the line and arrowhead. S is a character string made with one % element from any or all of the following 3 columns: % % Color Switches LineStyle LineWidth % ------------------ ------------------- -------------------- % k black (default) - solid (default) 0.5 points (default) % y yellow : dotted 0 no lines % m magenta -. dashdot / LineWidthOrder % c cyan -- dashed % r red * LineStyleOrder % g green % b blue % w white __________ __ % a apple green ^ | % d dark gray / \ | % e evergreen / \ | % f fuchsia / \ | % h honey / \ Height % i indigo / \ | % j jade / \ | % l lilac / \ | % n nutbrown /______ ______\ __|__ % p pink | | | | % q kumquat |---- Width ----| % s sky blue | | | | % t tan | | % u umber | | % v violet | | % z zinc -->| |<--LineWidth % x random named color | | % o ColorOrder % | magnitude % % The components of S may be specified in any order. Invalid % characters in S will be ignored and replaced by default settings. % % Prefixing the color code with '_' produces a darker shade, e.g. % '_t' is dark tan; prefixing the color code with '^' produces a % lighter shade, e.g. '^q' is light kumquat. The relative % brightness of light and dark color shades is controled by the % scalar parameter BETA. Color code prefixes do not affect the % basic colors (kymcrgbw) or the special color switches (xo|). % % ColorOrder may be achieved in two fashions: The user may either % set the ColorOrder property (using RGB triples) or define the % global variable ColorOrder (using a string of valid color codes). % If the color switch is specified with 'o', and the global variable % ColorOrder is a string of color codes (color switches less 'xo|', % optionally prefixed with '_' or '^'), then the ColorOrder property % will be set to the sequence of colors indicated by the ColorOrder % variable. If the color switch is specified with 'o', and the % global variable ColorOrder is empty or invalid, then the current % ColorOrder property will be used. Note that the ColorOrder % variable takes precedence over the ColorOrder property. % % The magnitude color switch is used to visualize vector magnitudes % in conjunction with a colorbar. If the color switch is specified % with '|', colors are linearly interpolated from the current ColorMap % according to the length of the associated line. This option sets % CLim to [MinM,MaxM], where MinM and MaxM are the minimum and maximum % magnitudes, respectively. % % The current LineStyleOrder property will be used if LineStyle is % specified with '*'. MATLAB cycles through the line styles defined % by the LineStyleOrder property only after using all colors defined % by the ColorOrder property. If however, the global variable % LineWidthOrder is defined, and LineWidth is specified with '/', % then each line will be drawn with sequential color, linestyle, and % linewidth. % % W is a vector of arrowhead widths. For linear plots with equal % axes, the units of W (default = 1/72 of the PlotBox diagonal) are % the same as those of the coordinate data (P1,P2). For linear plots % with unequal axes, the units of W are scaled to fit as if the axes % were equal. For log plots, the units of W (default = 1) are 1/72 % of the PositionRectangle diagonal. % % H (default = 3W) is a vector of arrowhead heights. If vector IP is % neither empty nor negative, initial point markers will be plotted % with diameter IP; for default diameter W, use IP = 0. The units of % W, H, and IP are absolute for linear plots and relative to the % PositionRectangle for log plots. % % ALPHA (default = 1) is a vector of FaceAlpha (MATLAB 6+) values % ranging between 0 (clear) and 1 (opaque). FaceAlpha is a surface % (arrowhead and initial point marker) property and does not affect % lines. FaceAlpha is not supported for 2D rendering. % % BETA (default = 0.4) is a scalar that controls the relative % brightness of light and dark color shades, ranging between 0 (no % contrast) and 1 (maximum contrast). % % Plotting lines with a single color, linestyle, and linewidth is % faster than plotting lines with multiple colors and/or linestyles. % Plotting lines with multiple linewidths is slower still. ARROW3 % chooses renderers that produce the best screen images; exported % or printed plots may benifit from different choices. % % HN = ARROW3(P1,P2,...) returns a vector of handles to line and % surface objects created by ARROW3. % % ARROW3 COLORS will plot a table of named colors with default % brightness. ARROW3('colors',BETA) will plot a table of named % colors with brightness BETA. % % If a particular aspect ratio is required, use DASPECT, PBASPECT, % AXIS, or XYZLIM commands before calling ARROW3. Changing limits % or aspect ratios after calling ARROW3 may alter the appearance % of arrowheads and initial point markers. ARROW3 sets XYZCLimMode % to manual for all plots, sets DataAspectRatioMode to manual for % linear plots, and sets PlotBoxAspectRatioMode to manual for log % plots and 3D plots. % % ARROW3 UPDATE will restore the the appearance of arrowheads and % initial point markers that have become corrupted by changes to % limits or aspect ratios. ARROW3('update',SF) will redraw initial % point markers and arrowheads with scale factor SF. If SF has one % element, SF scales W, H and IP. If SF has two elements, SF(1) % scales W and IP, and SF(2) scales H. If SF ha