You want a spiral?
1. Set x,y position = tempLoc
2. Loop for i from 1 to 'number of effects'
3. Change angle let's call it "a" so now, a = i x 10
4. Now the offset "o" let's have o = i x 10
5. Set tempLoc2 = tempLoc offset by o towards a degrees
Do you want rings?
1. Set x,y position = tempLoc
2. Loop for i from 1 to 36 and loop for i2 from 1 to however many rings you want
3. Change angle let's call it "a" so now, a = i x 10
4. Now the offset "o" let's have o = i x (i2 x 10)
5. Set tempLoc2 = tempLoc offset by o towards a degrees
Now both of these will decrease the frequency of occurrences as you move away from the center.
You want even spaces I believe. To do this use the distance of tempLoc2 from temploc. The larger that number gets ... remember it's called 'o' then smaller the angle multiplier should be. So now we have something like a = i x (10 - (o / 100)).
You will have to play around with it. I suggest making a configuration and setting the multipliers and dividers as variables too.
This is the basic structure, I'm sorry I'm not smart enough to spell it out exactly how you wanted it.