VectorPlot on a Circle

*To*: mathgroup at smc.vnet.net*Subject*: [mg114766] VectorPlot on a Circle*From*: "Dave Snead" <dsnead6 at charter.net>*Date*: Thu, 16 Dec 2010 05:49:46 -0500 (EST)*References*: <ie297c$mrj$1@smc.vnet.net> <201012130852.DAA09458@smc.vnet.net>

Hi, I'm trying to do a vector plot but confine the vectors to a unit circle. VectorPlot[ If[Abs[x^2 + y^2 - 1] == 0, {x, y}, {0, 0}], {x, -1, 1}, {y, -1, 1}] only plots a couple of vectors, not the dense set of vectors that I want. and VectorPlot[ If[Abs[x^2 + y^2 - 1] <.1, {x, y}, {0, 0}], {x, -1, 1}, {y, -1, 1}] plots lots of vectors but they're on an annulus rather than a circle. Is there any way to do this? Or more generally is there any way to confine the vectors to a curve. Or, kicking the dimension up by 1, can VectorPlot3D confine the vectors to a surface? Thanks, Dave Snead

**Follow-Ups**:**Re: VectorPlot on a Circle***From:*Murray Eisenberg <murray@math.umass.edu>

**Re: VectorPlot on a Circle***From:*Patrick Scheibe <pscheibe@trm.uni-leipzig.de>

**References**:**Re: vector/matrix indexed from zero***From:*Norbert Marxer <marxer@mec.li>