Abstract In this paper, we investigate the population of energetically dominant sunward-propagating Alfvén waves (SAWs) using more than 20 yr of data provided by the Wind spacecraft near 1 au. We refer to SAWs as energetically dominant sunward-propagating Alfvén waves within inertial range scales. Key parameters such as normalized cross helicity, plasma compressibility, and magnetic compressibility are used to determine the SAWs. Incorporating the polarity of the heliospheric magnetic field, Alfvén wave modes are identified, which enables the determination of the propagation direction. Occurrence rates of SAWs vary from 1% to 14% depending on the timescale and solar wind stream type considered. Particularly, the relationship between large-scale magnetic field switchbacks and SAWs (for a 1 hr long timescale) is investigated. A methodology utilizing pitch angle distributions of suprathermal electron strahl is employed to identify inverted magnetic field topology. The intervals containing SAWs are cross-referenced and examined with intervals identified as switchbacks . For a sample of 1636 1 hr SAW intervals, 17.5% are associated with magnetic field switchbacks occurring at scales larger than 1 hr. The analysis lends support to the idea of switchbacks as one of the candidate sources for a portion of the SAW population.
Giardetti et al. (Mon,) studied this question.