3D arrow tail properties

Question

I would like to use VectorPlot3D to plot a vector field with 3D arrows:

B1 = 0.0005;  (*G/μm*)
B2 = -2*B1;
b[x_, y_, z_, Bf_] := {B1*x, B1*y, B2*z + Bf};

VectorPlot3D[b[x, y, z, 0], {x, -13, 13}, {y, -13, 13}, {z, -13, 13}, 
             PlotRange -> {{-13, 13}, {-13, 13}, {-13, 13}}, 
             VectorScale -> {0.1, 1, None}, VectorPoints -> {6, 6, 5}, 
             VectorStyle -> {"Arrow3D", Red}, 
             RegionFunction -> Function[{x, y, z}, x^2 + y^2 + 2 z^2 < 13^2], 
             Boxed -> True, Axes -> False]

Is there a way to change the properties of the 3D arrow tails? For example, to make them thicker.

I'm guessing it has something to do with the Tube[] function, but I cannot quite figure it out.

Thanks in advance!

Answer 1

The answer comes directly from the help of VectorPlot3D under Options -> VectorStyle. There, it is shown how you can use customized graphics to tweak the appearance

g = {Graphics3D[Cylinder[{{0, 0, 0}, {1, 0, 0}}, 0.5]], 
   Graphics3D[Cone[{{-0.5, 0, 0}, {1.5, 0, 0}}, 0.5]]};

VectorPlot3D[{y, -x, z}, {x, -1, 1}, {y, -1, 1}, {z, -1, 1}, 
 VectorColorFunction -> Hue, VectorPoints -> 4, VectorStyle -> {g}, 
 VectorScale -> {Automatic, Scaled[0.3]}]

Update

You can always adjust the Tube directives in your final 3d graphics. For this, use a simple replacement, where you fix the tube radius. If gr is your graphics, the general approach looks like this:

gr /. Tube[pts_, r_] :> Tube[pts, r*scale]

To try it, you could include it into a dynamic Manipulate

Manipulate[
 gr = VectorPlot3D[
   b[x, y, z, 0], {x, -13, 13}, {y, -13, 13}, {z, -13, 13}, 
   PlotRange -> {{-13, 13}, {-13, 13}, {-13, 13}}, 
   VectorPoints -> {6, 6, 5}, VectorStyle -> {"Arrow3D", Red}, 
   RegionFunction -> Function[{x, y, z}, x^2 + y^2 + 2 z^2 < 13^2], 
   Boxed -> True, Axes -> False];
 gr /. Tube[pts_, r_] :> Tube[pts, r*scale],
 {{scale, 1}, 0, 2}
]