Counterstreaming strahls and dropouts observed in pitch angle distributions of suprathermal electrons as possible signatures of local particle acceleration in the solar wind

We present multi-spacecraft observations of pitch-angle distributions (PADs) of suprathermal electrons at ~1 AU which cannot be easily interpreted within the classical paradigm that all suprathermal electrons originate in the solar corona. We suggest that suprathermal electrons accelerated locally in the solar wind are mixed up with the well-known population of electrons of solar origin. Using PIC simulations, we show that key PAD features such as (i) heat flux dropouts and vertical PAD stripes encompassing reconnecting current sheets (RCSs), (ii) bi-directionality of strahls, and (iii) dramatically different PAD patterns observed in different energy channels can be explained by the behavior of electrons accelerated up to hundreds eV directly in the solar wind while thermal particles pass through local RCSs and/or dynamical 3D plasmoids (or 2D magnetic islands).