Need tips for optimizing main func that loops through thousands of particles

Hi!

I'm trying to create fractal images with the following equation.

And it should look something like this but in 3D

I've got everything right, and my script is below. But, I want to run 5 - 8 particle systems at once so I can create this effect! I've ran the profiler and the CPU spikes when it's calling GenerateOrbit(); I know the main concern is the fact that I'm looping through every particle to change their positions, but I'm not really sure if there's an alternative. Perhaps there is a better way of creating 9 particle systems by using fabrication & instantiating?

 #pragma strict
  
  var particleCount : int = 4000;
   
  
  function Start ()
  {
     GenerateOrbit();            
  }
  
  function FixedUpdate(){
     
     GenerateOrbit();
     
  }
  
  function GenerateOrbit(){
  
        // Figure out which range is best for BIG fractals  
      var a : int = Random.Range(-1,5);
      var b : int = Random.Range(-11,2);
       var c : int = Random.Range(-10,20);
     
      var myParticleSystem : ParticleSystem; 
      var myParticles: ParticleSystem.Particle[];
      
      
      myParticleSystem = GetComponent(ParticleSystem);
      myParticleSystem.startColor = new Color32(Mathf.Round(Random.Range(0,255)),Mathf.Round(Random.Range(0,255)),Mathf.Round(Random.Range(0,255)),255);
      myParticleSystem.Emit(particleCount);
      
      myParticles = new ParticleSystem.Particle[particleCount + 1];
      myParticleSystem.GetParticles(myParticles);
      
      var x : float;
      var y : float;
      var prevPos : Vector3;
         
      for (var i = 0; i < particleCount; i++)
      {
          // Get previous particle position
          prevPos = (i < 1) ? new Vector3(Random.Range(-5,10), Random.Range(-5,10)) : myParticles[i - 1].position; // Perhaps Random.value isn't the best option here? 
          
          x = prevPos.x;
          y = prevPos.y;
          
          // For the sake of optimizing by not using Mathf.sqrt & Mathf.abs
          x_abs = (x > 0 ? x : -x);
          var d : float;
          d = (b * x + c) > 0 ? (b * x + c) : -(b * x + c);
          d = Mathf.Pow(d_abs,0.5); 
            
          var x1 = y - x / x_abs * d;
          var y1 = a - x;
          
          var newPosition = new Vector3(x1, y1, 0);
          
          myParticles[i].position = newPosition;
          myParticleSystem.SetParticles(myParticles, particleCount);
      }
      
     yield WaitForSeconds(5);
     myParticleSystem.Clear();
  }