Script works with ParticleSystem but not ParticleSystem []

Hello,
I am new to Unity and I would like to select a group of more than 10 ParticleSystem, to go faster I use “[ ]” but I get an error when I add “[ ]” after ParticleSystem.

Here is the part of the code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;


    public class OptionManager : MonoBehaviour
    {

        public Slider SliderParticle;
        public ParticleSystem[] PS;
        public float hSliderValue = 5.0f;

void Start()
        {
            var emission = PS.emission;
            emission.rateOverTime = 0.0f;
        }

void Update()
        {
                hSliderValue = SliderParticle.value;
                var emission = PS.emission;
                emission.rateOverTime = SliderParticle.value;

            }

I’m trying to change the “rateOverTime” value of all the particles from a slider from 1 to 20

PS is an array. As such it holds ParticleSystem. To retrieve a ParticleSystem from that array you have to give it an ID. Cycle through the IDs with a loop. Like this:

for(int i = 0; i < PS.Length; i++)
{
    var emission = PS[i].emission;
    emission.rateOverTime = SliderParticle.value;
}