Listed are all scientific papers resulting from an ISSI activity written or co-authored by ISSI Team members, Working Group members, Workshop participants, visitors or staff members.
Since the Voyager mission flybys in 1979, we have known the moon Io to be both volcanically active and the main source of plasma in the vast magnetosphere of Jupiter. Material lost from Io forms neutral clouds, the Io plasma torus and ultimately the extended plasma sheet. This material is supplied from Io’s upper atmosphere and atmospheric loss is likely driven by plasma-interaction effects with possible contributions from thermal escape and photochemistry-driven escape.
The physical processes in the solar corona that shape the solar wind remain an active research topic. Modeling efforts have shown that energy and plasma exchanges near the transition region play a crucial role in modulating solar wind properties. Although these regions cannot be measured in situ, plasma parameters can be inferred from coronal spectroscopy and ionization states of heavy ions, which remain unchanged as they escape the corona.
Context. Extreme solar particle events (ESPEs) were identified almost a decade ago, providing context for super events unleashed by our host star, the Sun. Their assumed solar origin drives the question of their “worst-case” impact, which could be profound, multifaceted, and devastating for our technological society. Aims.
Context. We investigate the behavior of the plasma in eruptive prominences and coronal mass ejections in characteristic physical conditions. Aims. We aim to demonstrate various relations between the plasma parameters and radiation properties relevant to Solar Orbiter and Metis observations. Methods. Our method is based on 2D non-local thermodynamic equilibrium (non-LTE) modeling of moving structures that are externally illuminated from the solar disk.
Context. Parker Solar Probe and Solar Orbiter have revealed the ubiquitous presence of magnetic switchbacks and jets in solar wind forming close to the Sun. While many studies suggest a causal link via solar magnetic reconnection, the specific mechanisms remain unclear. Some numerical simulations propose that small flux ropes generated within reconnecting current sheets could escape with the expanding solar wind, causing the measured velocity spikes.
In 2024 May, the scientific community observed intense solar eruptions that resulted in a great geomagnetic storm and auroral extensions, highlighting the need to document and quantify these events. This study mainly focuses on their quantification. The source active region (AR; NOAA Active Region 13664) evolved from 113 to 2761 millionths of the solar hemisphere between May 4 and 14. NOAA AR 13664’s magnetic free energy surpassed 1033 erg on May 7, triggering 12 X-class flares on May 8–15.
We compare two candidate nonlinearities for regulating the solar cycle within the Babcock–Leighton paradigm: tilt quenching (whereby the tilt of active regions is reduced in stronger cycles) and latitude quenching (whereby flux emerges at higher latitudes in stronger solar cycles). Digitized historical observations are used to build a database of individual magnetic plage regions from 1923 to 1985.
We observed the new long-period comet C/2024 E1 (Wierzchos), inbound at 7 au from the Sun, using the Near-Infrared Spectrograph (NIRSpec) integral field unit on JWST. The spectrum shows absorption features due to water ice in the coma and evidence for CO$_2$ driven activity, with a production rate of $Q(mathrm{ CO}_2) = 2.546 pm 0.019 times 10^{25}$ molecules s$^{-1}$, and no emission features of water or CO.
Nonthermal particle acceleration in the solar corona is evident from both remote hard X-ray sources in the chromosphere and direct in situ detection in the heliosphere. Correlation of spectral indices between remote and in situ energy spectra presents the possibility of a common source-acceleration region within the corona, however the properties and location of this region are not well constrained.
Using Mars Atmosphere and Volatile EvolutioN Magnetometer observations, we report the first statistical study of ultralow frequency (ULF) waves at the Martian foreshock. The analyzed foreshock ULF wave events are observed in the 0.008–0.086 Hz frequency range, with nearly circular and elliptical left-handed polarization in the spacecraft reference frame. These waves are propagated quasi-parallel to the ambient magnetic field, with a moderate wave amplitude.
