Jaynes joined the faculty at the University of Iowa in 2017 after receiving a PhD from the University of New Hampshire and working as a researcher at the University of Colorado Boulder. Her research focuses on inner magnetosphere particle dynamics, including the ring current and radiation belts and how they connect to atmospheric and auroral physics. She has been a Co-Investigator on the MMS and Van Allen Probes NASA satellite missions. She is currently serving as co-lead on the SCOSTEP PRESTO committee for predictions of the Sun-Earth environment, as a member of the AGU Nomination Task Force, and as a member of the National Academies study on Increasing PI Diversity and Inclusion in the Leadership of Competed Space Missions. She previously served as co-chair of the Geospace Dynamics Constellation (GDC) Science and Technology Definitions Team for NASA. She was awarded an NSF CAREER in 2020. 

She is currently advising one postdoctoral researcher and four PhD students, and was a recipient of the University of Iowa Postdoctoral Association Mentor Award. She teaches multiple courses including a newly developed course on spaceflight hardware (The Edge of Space: Mission and Instrument Design for Spaceflight).