Version: 2020.3
public bool loop ;


Specifies whether the Particle System is looping.

If you disable looping on a playing Particle System, it stops at the end of the current loop.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { private ParticleSystem ps;

void Start() { ps = GetComponent<ParticleSystem>();

var main = ps.main; main.loop = true; } }