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We discuss features of coronal mass ejections (CMEs) that are specific to heliospheric observations at large elongation angles. Our analysis is focused on a series of two eruptions that occurred on 2007 January 24-25, which were tracked by the Heliospheric Imagers (HIs) onboard STEREO. Using a three-dimensional (3-D) magneto-hydrodynamic simulation of these ejections with the Space Weather Modeling Framework (SWMF), we illustrate how the combination of the 3-D nature of CMEs, solar rotation, and geometry associated with the Thomson sphere results in complex effects in the brightness observed by the HIs. Our results demonstrate that these effects make any in-depth analysis of CME observations without 3-D simulations challenging. In particular, the association of bright features seen by the HIs with fronts of CME-driven shocks is far from trivial. In this Letter, we argue that, on 2007 January 26, the HIs observed not only two CMEs, but also a dense corotating stream compressed by the CME-driven shocks.
AIM: Large amplitude narrowband obliquely propagating whistler-mode waves at frequencies of ~0.2 fce (electron cyclotron frequency) are commonly observed at 1 AU, and are most consistent with the whistler heat flux fan instability. We want to determi
In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light c
Context. The Rosetta spacecraft made continuous measurements of the coma of comet 67P/ Churyumov-Gerasimenko (67P) for more than two years. The plasma in the coma appeared very dynamic, and many factors control its variability. Aims. We wish to ident
In this study we present an inversion method which provides thermal plasma population parameters from characteristics of chorus emissions only. Our ultimate goal is to apply this method to ground based data in order to derive the lower energy boundar
The recently released spacecraft potential measured by the RPW instrument on-board Solar Orbiter has been used to estimate the solar wind electron density in the inner heliosphere. Solar-wind electron density measured during June 2020 has been analys