Drake, Jeremy J.Gomez, Julián AlvaradoArgiroffi, CostanzaFlaccomio, EttoreGarraffo, CeciliaGrosso, NicolasIslam, NazmaKarovska, MargaritaKashyap, Vinay L.Monsch, KristinaNess, Jan-UweSciortino, SalvatoreWargelin, Bradford2023-11-282023-11-282023-10-26https://doi.org/10.48550/arXiv.2310.17563http://hdl.handle.net/11603/30909We outline some of the highlights of the scientific case for the advancement of stellar high energy physics using the Line Emission Mapper X-ray Probe ({\it LEM}). The key to advancements with LEM lie in its large effective area -- up to 100 times that of the {\it Chandra} MEG -- and 1~eV spectral resolution. The large effective area opens up for the first time the ability to study time-dependent phenomena on their natural timescales at high resolution, such as flares and coronal mass ejections, and also opens the sky to much fainter targets than available to {\it Chandra} or {\it XMM-Newton}.29 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.Text