Eugene Newman Parker (June 10, 1927 – March 15, 2022) was an American solar and plasma physicist.

In 1987, Parker proposed the existence of nanoflares, a leading candidate to explain the coronal heating problem.

Parker obtained his PhD from Caltech and spent four years as a postdoctoral researcher at the University of Utah.

His theoretical modeling was not immediately accepted by the astronomical community: when he submitted the results to The Astrophysical Journal, two reviewers recommended its rejection.

In 1972, he formulated what became known as the Parker theorem, which showed how the topology of magnetic field lines in the solar corona of the Sun (and similar stars) can produce flares at X-ray energies.