A metadata schema, named Plasma-MDS, is introduced to support research data management in applied plasma science and plasma medicine. Plasma-MDS is suitable to facilitate the publication of research data following FAIR principles in domain-specific repositories and with this the reuse of research data for data driven plasma science. The metadata schema takes into account common features of research in applied plasma science and plasma medicine. This is expressed by the choice of basic schema elements, namely "plasma.source", "plasma.medium", and "plasma.target". These schema elements reflect the fact that most research data in the scientific domain under consideration refer to a plasma source that is operated in a certain medium and usually acting on a specific target. This novel metadata schema is first applied for the annotation of datasets published in INPTDAT -- the interdisciplinary data platform for plasma technology.