Fusion and plasma physics ethics are of course no different than ethics in any other discipline. Ethics is not usually taught at technical universities, or only as an optional course. And yet all workers in the field are supposed to be aware of and abide by ethical rules that are not made explicit or formalized anywhere. This makes it hard to know which behaviour is correct, especially so when the field is international and workers originate from different cultures and religious backgrounds.
In general, it seems reasonable to abide by the famous Golden Rule:
One should not treat others in ways that one would not like to be treated.
Below follow some examples of ethics issues in fusion and plasma physics.
In fusion and plasma physics, publication author lists tend be ordered according to the decreasing importance of each author to the work. Occasionally, authors are included for political reasons. This may be acceptable provided the first few authors are still the ones who have contributed most, so the work is accounted for properly in citation indexes.
Many of the works in this field are the result of work by many people. It is often unclear who should be included in the author list, apart from the main contributors. Typically, each laboratory has its own rules in this respect, but the general principle should be that at least anyone who contributed directly should be included.
A common practice is the inclusion of team names in the author list. This seems rather pointless when it is not established clearly who are the team members, as the team members cannot then claim the publication as their own.
In publications, there is a natural tendency to cite only work by 'friendly groups' or work supporting the thesis one is trying to prove. It would be preferable to try to reduce bias, by also citing work by 'competing' groups, when appropriate, and even work contradicting one's own conclusions, as this may stimulate discussion and may be helpful in the resolution of contradictions or unclear issues. Up to a point, it is the task of referees to detect missing references.
In the field of fusion and plasma physics, refereeing is mostly anonymous. This protection of the referee may be advantageous from the point of view of obtaining honest reviews, but requires a high level of ethical conduct by the referees. When a referee detects a conflict of interest (e.g., he pertains to a group competing for funds with the author's group) so that he is unlikely to make an objective judgment, he should refrain from acting as referee.
The referee comments should be objective, refrain from gratuitous disqualifications, and be phrased in respectful language. All comments should be sufficiently concrete to allow a response (e.g., a comment like 'I disapprove of this method' is unacceptable without specifying why exactly one disapproves).
From the participation by women scientists in conferences it is clear that women are still a minority in the field, as in many technical and applied fields.  It is hard to be sure why this is so, and to what degree discrimination (or even self-exclusion) plays a role. Most likely, discrimination exists although not in a very explicit manner, and hence hard to combat, as the discriminators may not even be aware of their bias to favour men over women for certain tasks or posts or in communications. It may be useful to appoint a commission to monitor and correct undesirable behaviour.
Similar arguments can be made regarding other types of discrimination (based on race, religion, etc.).
Work relations between unequals
As in any other work environment, there exist huge power differences between, e.g., established scientists possessing influence and contacts, and students or junior scientists. Using power without abusing it is clearly an ethical issue and requires restraint and self-control by the influential party. One should strive towards fair and equal treatment. High level scientists should exercise some degree of mutual control to guarantee compliance with this principle.