  An important and perhaps dominant source of dust in the martian atmosphere,
dust devils play a key role in Mars' climate. Datasets from previous landed
missions have revealed dust devil activity, constrained their structures, and
elucidated their dust-lifting capacities. However, each landing site and
observational season exhibits unique meteorological properties that shape dust
devil activity and help illuminate their dependence on ambient conditions. The
recent release of data from the Mars Environmental Dynamics Analyzer (MEDA)
instrument suite onboard the Mars 2020 Perseverance rover promises a new
treasure-trove for dust devil studies. In this study, we sift the time-series
from MEDA's Pressure Sensor (PS) and Radiative and Dust Sensors (RDS) to look
for the signals of passing vortices and dust devils. We detected 309 vortex
encounters over the mission's first 89 sols. Consistent with predictions, these
encounter rates exceed InSight and Curiosity's encounter rates. The RDS
time-series also allows us to assess whether a passing vortex is likely to be
dusty (and therefore is a true dust devil) or dustless. We find that about one
quarter of vortices show signs of dust-lofting, although unfavorable encounter
geometries may have prevented us from detecting dust for other vortices. In
addition to these results, we discuss prospects for vortex studies as
additional data from Mars 2020 are processed and made available.
