user33694: 
I'm trying to achieve this effect on After Effects with Trapcode Form plugin, because it's particles around the edges with hollow center, I thought it's got to be the spherical field, so I created box-string base form and cranked up the spherical field and I ended up with similar result

how ever soon I realized the strings around the circle is in segments rather than a continuous line, it becomes more obvious when it's in motion, I'm curious to know how it's supposed to be done, thanks!!!

user4426: The "Ring Emitter" preset in Trapcode Particular gets pretty close to this - you could probably use it as a starting point.
Look in the Presets tab on the left under "Spline Primitives".


33694: <p><a href="https://i.stack.imgur.com/l00D7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/l00D7.png" alt="enter image description here" /></a></p>
<p>I'm trying to achieve this effect on After Effects with Trapcode Form plugin, because it's particles around the edges with hollow center, I thought it's got to be the spherical field, so I created box-string base form and cranked up the spherical field and I ended up with similar result
<a href="https://i.stack.imgur.com/0BxCP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0BxCP.png" alt="enter image description here" /></a></p>
<p>how ever soon I realized the strings around the circle is in segments rather than a continuous line, it becomes more obvious when it's in motion, I'm curious to know how it's supposed to be done, thanks!!!</p>
 4426: <p>The &quot;Ring Emitter&quot; preset in Trapcode Particular gets pretty close to this - you could probably use it as a starting point.</p>
<p>Look in the Presets tab on the left under &quot;Spline Primitives&quot;.</p>
<p><a href="https://i.stack.imgur.com/N31uX.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N31uX.jpg" alt="screengrab" /></a></p>
