There are a few different types of plasma found in PlanetSide, all of them dangerous. All types continue to do damage after the initial impact. Soldiers can only take two instances of this secondary damage at the same time. Additional instances are ignored until the first one wears off. Note, however, that the damage taken from the initial impact is unlimited.
The first and most common occurance of the fourth state of matter.
These aggravated-damage plasma fields are Anti-Vehicular in nature, being distributed by the orbs of the Starfire and Comet MAXes, as well as the Starfire BFR Weapon of the Vanu Sovereignty. Soldiers taking damage from this type of plasma glow purple.
A Gunner weapon only, these are long-range ballistic mortars intended to injure infantry. Soldiers taking damage from this type of plasma flash white.
Though technically not plasma, taking burn damage from the Dragon has very similar effects to plasma and shares the maximum of 2 instances of burn damage from the secondary fire mode. Soldiers burning from the Dragon will glow orange.