Search Publications
The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29
Kulkarni, S. R.; Lario, D.; Laitinen, T. +66 more
Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (≲1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe, the Solar Terrestrial Relations Ob…
Magnetic helicity and energy budget around large confined and eruptive solar flares
Veronig, A. M.; Thalmann, J. K.; Gupta, M.
Context. In order to better understand the underlying processes and prerequisites for solar activity, it is essential to study the time evolution of the coronal magnetic field of solar active regions (ARs) associated with flare activity.
Aims: We investigate the coronal magnetic energy and helicity budgets of ten solar ARs around the times of…
First light observations of the solar wind in the outer corona with the Metis coronagraph
Heinzel, P.; Vial, J. -C.; Woch, J. +65 more
In this work, we present an investigation of the wind in the solar corona that has been initiated by observations of the resonantly scattered ultraviolet emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscop…
Modelling a multi-spacecraft coronal mass ejection encounter with EUHFORIA
Palmerio, E.; Temmer, M.; Poedts, S. +6 more
Context. Coronal mass ejections (CMEs) are a manifestation of the Sun's eruptive nature. They can have a great impact on Earth, but also on human activity in space and on the ground. Therefore, modelling their evolution as they propagate through interplanetary space is essential.
Aims: EUropean Heliospheric FORecasting Information Asset (EUHF…
Generation of interplanetary type II radio emission
Jebaraj, I. C.; Mann, G.; Poedts, S. +4 more
Context. Coronal mass ejections (CMEs) are eruptive phenomena that can accelerate energetic particles and drive shock waves. The CME-driven shocks propagate from the low corona to interplanetary space. The radio emission that results from fast electrons energised by shock waves are called type II bursts. This radio emission can provide information…
PSP/IS⊙IS observations of the 29 November 2020 solar energetic particle event
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +24 more
Aims: On 29 November 2020, at 12:34 UT, active region 12790 erupted with an M4.4 class flare and a 1700 km s−1 coronal mass ejection. Parker Solar Probe (PSP) was completing its seventh orbit around the Sun and was located at 0.8 au when the Integrated Science Investigation of the Sun (IS⊙IS) measured the ensuing mid-sized solar en…
Sunspot tilt angles revisited: Dependence on the solar cycle strength
Jiang, Jie; Jiao, Qirong; Wang, Zi-Fan
Context. The tilt angle of sunspot groups is crucial in the Babcock-Leighton (BL) type dynamo for the generation of the poloidal magnetic field. Some studies have shown that the tilt coefficient, which excludes the latitudinal dependence of the tilt angles, is anti-correlated with the cycle strength. If the anti-correlation exists, it will be show…
Uncovering erosion effects on magnetic flux rope twist
Pal, Sanchita; Pomoell, Jens; Price, Daniel J. +2 more
Context. Magnetic clouds (MCs) are transient structures containing large-scale magnetic flux ropes from solar eruptions. The twist of magnetic field lines around the rope axis reveals information about flux rope formation processes and geoeffectivity. During propagation MC flux ropes may erode via reconnection with the ambient solar wind. Any eros…
Solar origins of a strong stealth CME detected by Solar Orbiter
Long, David M.; Möstl, Christian; Davies, Emma E. +6 more
Aims: We aim to locate the origin of a stealth coronal mass ejection (CME) detected in situ by the MAG instrument on board Solar Orbiter and make connections between the CME observed at the Sun and the interplanetary CME (ICME) measured in situ.
Methods: Remote sensing data were analysed using advanced image processing techniques to iden…
The unusual widespread solar energetic particle event on 2013 August 19. Solar origin and particle longitudinal distribution
Williams, D.; Jian, L. K.; Rodríguez-Pacheco, J. +11 more
Context. Late on 2013 August 19, STEREO-A, STEREO-B, MESSENGER, Mars Odyssey, and the L1 spacecraft, spanning a longitudinal range of 222° in the ecliptic plane, observed an energetic particle flux increase. The widespread solar energetic particle (SEP) event was associated with a coronal mass ejection (CME) that came from a region located near th…