private void createSpark(){
                AssetManager assetManager = getApplication().getAssetManager();
                spark = new ParticleEmitter("Spark", ParticleMesh.Type.Triangle, 30 );
                spark.setStartColor(new ColorRGBA(1f, 0.8f, 0.36f, 1.0f));
                spark.setEndColor(new ColorRGBA(1f, 0.8f, 0.36f, 0f));
                spark.setStartSize(.5f);
                spark.setEndSize(.5f);
                spark.setFacingVelocity(true);
                spark.setParticlesPerSec(0);
                spark.setGravity(0, 5, 0);
                spark.setLowLife(1.1f);
                spark.setHighLife(1.5f);
                spark.getParticleInfluencer().setInitialVelocity(new Vector3f(0, 20, 0));
                spark.getParticleInfluencer().setVelocityVariation(1);
                spark.setImagesX(1);
                spark.setImagesY(1);
                Material mat = new Material(assetManager, "Common/MatDefs/Misc/Particle.j3md");
                mat.setTexture("Texture", assetManager.loadTexture("Effects/Explosion/spark.png"));
                spark.setMaterial(mat);
                explosionEffect.attachChild(spark);
            }
This test's particle effects (using an explosion)
jme3-screenshot-tests/src/test/java/org/jmonkeyengine/screenshottests/effects/TestExplosionEffect.java