If you want to do any sort of scientific programming you will need to obtain a PhD and then land a job at a research lab, university, or boutique software compa

If you want to do any sort of scientific programming you will need to obtain a PhD and then land a job at a research lab, university, or boutique software company. These jobs are all over but you will probably have to fight hard to get one and then fight even harder to keep it and get your project funded. Even scientists in top national laboratories probably constantly worry about funding. An alternate route is to start a company around a new software product. If you manage to find a scientific programming job at an existing company and that job is not protected from the non-technical business in some way, your project will be in constant jeopardy. As for field, you will have to determine what type of work you want to do. I would suggest reading some academic papers on the type of work you would like to do and then look at the path that the authors followed. You can also contact the authors and express an interest. They will probably point you towards an exploitative grad student job making 15-20k / year, but you will probably get to do some sort of scientific programming.