Ah (interj.)
An exclamation, expressive of surprise, pity, complaint, entreaty, contempt, threatening, delight, triumph, etc., according to the manner of utterance.
Ha (interj.)
An exclamation denoting surprise, joy, or grief. Both as uttered and as written, it expresses a great variety of emotions, determined by the tone or the context. When repeated, ha, ha, it is an expression of laughter, satisfaction, or triumph, sometimes of derisive laughter; or sometimes it is equivalent to \"Well, it is so.\"