Dr. Cohen is interested in the natural electricity of the Earth, including lightning, the electrically charged upper atmosphere, and the radiation-filled space environment. He uses radio waves at low frequencies measured all around the world to understand them, and develops resulting practical applications. His group also works on novel techniques to generate low frequency waves with nonconventional electrically-short antennas. He is an author of more than 60 journal publications. He employs a “flipped classroom” model in some of his courses to make the experience more active and engaging.