@eind45 - If I understand your question, I can give you one data set in response. My son is a senior majoring in aerospace engineering. He is interested in electric-plasma propulsion and his number one choice is the University of Michigan’s Plasmadynamics and Electric Propulsion Laboratory http://pepl.engin.umich.edu/about.html. The lab is directed by the University’s Aerospace Engineering department, but there are a large number of grad students in the program who were physics majors in college and two out of the last three PhD theses were submitted to fulfill the requirements for a PhD in applied physics. Multiple professors are listed as advisors, many from different departments and I have seen advisors who were even from another university.