Usiing Vector3 to build a pinball table bumper

Hi all, I am trying to build a bumper for my Pinball table in Unity, to bounce the ball away with some force. I have tried using Vector3.forward but this just propells the ball directly up the table, and I want the bumper to simply push the ball away from itself, like in the picture.

Any help would be appreciated :)

here is my code: public class BumperPlateScript : MonoBehaviour { public float power = 100f; List ballList;

 void Start()
 {
     ballList = new List<Rigidbody>();
 }
 void OnTriggerEnter(Collider other)
 {
     if (other.gameObject.CompareTag("Ball"))
     {
         ballList.Add(other.gameObject.GetComponent<Rigidbody>());
         foreach (Rigidbody r in ballList)
         {
             r.AddForce(power * Vector3.forward);
         }
     }
 }

}