public void setParticlesPerSec(float particlesPerSec) {
        this.particlesPerSec = particlesPerSec;
        timeDifference = Math.min(timeDifference, 1f / particlesPerSec);
        //prevent large accumulated timeDifference from causing a huge number of particles to be emitted
    }
Set the number of particles to spawn per
second.

@param particlesPerSec the number of particles to spawn per
    second.
jme3-core/src/main/java/com/jme3/effect/ParticleEmitter.java