Is it alright to reapply to a PhD program you got rejected from if you work on your application? The main weakness in my application was my weak research experience in the field I applied to. Say I got two new writing samples and greatly improved my research experience. Would it be acceptable for me to reapply to a school I got rejected from? I really want to go to that program.
Generally yes (with improvements). Consider emailing their admissions to make sure they don't have a policy against reconsidering applicants some time later.