NICER observation list: Target ID 858801

Polars are cataclysmic variables with strong white dwarf (WD) magnetic fields that inhibit the formation of accretion disks. Two puzzling observational properties - the presence of soft X-ray blackbody emission in some polars and the absence of QPOs - have challenged our fundamental understanding of plasma instabilities in magnetically-confined radiative cooling accretion flows over three decades. NICER ToO observations of 15 polars in their X-ray bright states, through monitoring 45 targets with Einstein Probe, aim to provide the most sensitive probe yet of blobby accretion flows and long-sought X-ray QPOs predicted by recent theoretical models and simulations. These NICER observations will also complement the ongoing NuSTAR hard X-ray survey of polars by improving WD mass measurements.