What you will need...
Firstly, next to your "Lead" emitter you will need to create a 'new particle sprite emitter' and name it "Trail".
INITIAL VELOCITY (SEED)
COLOR OVER LIFE
--- EMITTER INITIAL LOCATION ---
SIZE BY LIFE
I'll wrap up the fire orb particle by adding:
- Mesh Data
- and a pulsing effect
Changing the Type data to GPU sprites is just a better option to use when wanting to have a large amount of particles spawning.
This will make some particles die after 0.6 secs and others to die after 1.2 secs. This will be most noticeable at the end of the trail.
As far as I am aware, the random seed info picks locations in space for the particles to spawn the same way each time this particle system starts up.
*Need to test further*
Increasing this number will increase the area in which the particles will spawn.
This is found under 'Attraction' once a particle sprite emitter is changed to GPU Sprites.
This parameter references the "Lead" particle emitter to get each particles position for the 'Trail' to emit.