Search Publications
Radial evolution of interplanetary coronal mass ejection-associated particle acceleration observed by Solar Orbiter and ACE
Li, Gang; Kouloumvakos, Athanasios; Wimmer-Schweingruber, Robert F. +5 more
On 2022 March 10 a coronal mass ejection erupted from the Sun, resulting in Solar Orbiter observations at 0.45 au of both dispersive solar energetic particles arriving prior to the interplanetary coronal mass ejection (ICME) and locally accelerated particles near the ICME-associated shock structure as it passed the spacecraft on 2022 March 11. Thi…
Solar energetic particles injected inside and outside a magnetic cloud: The widespread solar energetic particle event on 2022 January 20
Palmerio, E.; Jebaraj, I. C.; Laitinen, T. +22 more
Context. On 2022 January 20, the Energetic Particle Detector (EPD) on board Solar Orbiter measured a solar energetic particle (SEP) event showing unusual first arriving particles from the anti-Sun direction. Near-Earth spacecraft separated by 17° in longitude to the west of Solar Orbiter measured classic anti-sunward-directed fluxes. STEREO-A and …
Determining the acceleration regions of in situ electrons using remote radio and X-ray observations
Jebaraj, I. C.; Vainio, R.; Kilpua, E. K. J. +13 more
Context. Solar energetic particles in the heliosphere are produced by flaring processes on the Sun or by shocks driven by coronal mass ejections. These particles are regularly detected remotely as electromagnetic radiation (X-rays or radio emission), which they generate through various processes, or in situ by spacecraft monitoring the Sun and the…
Using the STIX background detector as a proxy for GOES
Volpara, Anna; Krucker, Säm; Dickson, Ewan C. M. +4 more
Context. The Spectrometer/Telescope for Imaging X-Rays (STIX) on board Solar Orbiter was designed to observe solar flares in the X-ray range of 4‑150 keV, providing spectral, temporal, and spatial information. Besides 30 imaging detectors, STIX has two additional detectors: the coarse flare locator (CFL) and the background (BKG) detector, which ar…
Stereoscopic observations reveal coherent morphology and evolution of solar coronal loops
Peter, H.; Chitta, L. P.; Plaschke, F. +2 more
Coronal loops generally trace magnetic lines of force in the upper solar atmosphere. Understanding the loop morphology and its temporal evolution has implications for coronal heating models that rely on plasma heating due to reconnection at current sheets. Simultaneous observations of coronal loops from multiple vantage points are best suited for …
Coronal hole picoflare jets are progenitors of both fast and Alfvénic slow solar wind
Livi, S.; Peter, H.; Chitta, L. P. +19 more
Solar wind, classified by its bulk speed and the Alfvénic nature of its fluctuations, generates the heliosphere. The elusive physical processes responsible for the generation of the different types of this wind are a topic of active debate. Recent observations reveal intermittent jets, with kinetic energy in the picoflare range, emerging from dark…
A new method for determining the onset times of solar energetic particles and their uncertainties: Poisson-CUSUM bootstrap hybrid method
Gutiérrez, C. P.; Vainio, R.; Dresing, N. +2 more
Context. Solar energetic particle (SEP) events are a type of space weather phenomena in which highly energetic charged particles are released from the Sun into interplanetary space by violent and eruptive phenomena, such as solar flares and coronal mass ejections. In order to assess the origin of SEPs, an accurate timing of their arrival at spacec…
Localizing short-period pulsations in hard X-rays and γ-rays during an X9.0 flare
Li, Dong
Context. The feature of quasi-periodic pulsations (QPPs) is frequently observed in the light curve of solar and stellar flares. However, the short-period QPP is rarely reported in the high energy range of hard X-rays (HXRs) and γ-rays. Aims. We investigated the QPP at a shorter period of about 1 s in high-energy channels of HXRs and γ-ray continuu…
Estimating uncertainties in the back-mapping of the fast solar wind
Dolla, L.; Keppens, R.; Koukras, A.
Context. Although the most likely source regions of fast solar wind relate to coronal holes, the exact acceleration mechanism that drives the fast solar wind is still not fully understood. An important approach that can improve our understanding involves the combination of remote sensing and in situ measurements, often referred to as linkage analy…
Flaring together: A preferred angular separation between sympathetic flares on the Sun
Strugarek, A.; Charbonneau, P.; Guité, L. -S.
Context. Sympathetic solar flares are eruptions that occur nearby in space and time, driven by an apparent interaction between the active regions in which they are triggered. Their statistical existence on the Sun has yet to be firmly established. Aims. The main goal of this paper is to identify a statistical signature of sympathetic flares, chara…