void StopParticleProcess()
 {
     if (thisProcess != null && thisProcess.IsRunning())
     {
         thisProcess.Stop();
     }
     thisProcess = null;
 }
 void StartParticleProcess()
 {
     StopParticleProcess();
     thisProcess = thisSlickBowShootingProcessFactory.CreateDestroyedTargetParticleProcess(
         this,
         particleSystemLifeTime
         );
     thisProcess.Run();
 }