AUTHOR=da Silva Daniel E., Elkington Scot R., Li Xinlin , Hudson M K., Boyd Alexander , Jaynes Allison , Wiltberger Michael TITLE=Radiation Belt Phase Space Density: Calculation Analysis and Model Dependence JOURNAL=Frontiers in Astronomy and Space Sciences VOLUME=11 YEAR=2024 URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2024.1423545 DOI=10.3389/fspas.2024.1423545 ISSN=2296-987X