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In this paper we examine suprathermal He ions measured by the SIT (Suprathermal Ion Telescope) instrument associated with tilted corotating interaction regions (CIRs). We use observations of the two STEREO spacecraft (s/c) for the first 2.7 years of the mission, along with ground-based measurements of the solar magnetic field during the unusually long minimum of Solar Cycle 23. Due to the unique configuration of the STEREO s/c orbits we are able to investigate spatial variations in the intensity of the corotating ions on time scales of less than one solar rotation. The observations reveal that the occurrence of the strong CIR events was the most frequent at the beginning of the period. The inclination of the heliospheric current sheet relative to the heliographic equator (the tilt angle) was quite high in the first stage of the mission and gradually flattened with the time, followed by a decrease in the CIR activity. By examining the differences between measurements on the two STEREO s/c we discuss how the changes in the position of the s/c relative to the CIRs affect the energetic particle observations. We combine STEREO observations with observations from the ULEIS instrument on the ACE s/c and argue that the main factor which controls the differences in the ion intensities is the latitudinal separation between the two STEREO s/c relative to the tilted CIRs. The position of the s/c is less important when the tilt angle is high. In this case we found that the CIR ion intensity positively correlates with the tilt angle.
We present observations from the Rosetta Plasma Consortium of the effects of stormy solar wind on comet 67P/Churyumov-Gerasimenko. Four corotating interaction regions (CIRs), where the first event has possibly merged with a CME, are traced from Earth
We report observations of the acceleration and trapping of energetic ions and electrons between a pair of corotating interaction regions (CIRs). The event occurred in Carrington Rotation 2060. Observed at spacecraft STEREO-B, the two CIRs were separa
We study periods of elevated energetic particle intensities observed by STEREO-A when the partial pressure exerted by energetic ($geq$83 keV) protons ($P_{EP}$) is larger than the pressure exerted by the interplanetary magnetic field ($P_{B}$). In th
We introduce a new solar energetic particle (SEP) transport code that aims at studying the effects of different solar wind configurations on SEP events. We focus on the influence of varying solar wind velocities on the energy changes of SEPs, and stu
The Parker Solar Probe was launched on 2018 August 12 and completed its second orbit on 2019 June 19 with perihelion of 35.7 solar radii. During this time, the Energetic particle Instrument-Hi (EPI-Hi, one of the two energetic particle instruments co