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.
The European Space Agency’s Rosetta mission is the only space mission that has performed long-term monitoring of a comet at close distances. For over two years, Rosetta rendezvoused with comet 67P/Churyumov–Gerasimenko, which revealed diverse evolutionary processes of the cometary nucleus. One of the most striking events is the migration of a ∼30 m boulder in the southern hemisphere region of Khonsu.
The Sun rarely produced extreme solar particle events (ESPEs), orders of magnitude stronger than everything directly observed. Their enormous power can greatly distort the production of cosmogenic isotopes, e.g., radiocarbon 14C, in the terrestrial system, leaving clear signatures in natural terrestrial archives including dateable tree rings. Eight such events were known to occur during the past 12 millennia of the Holocene, with the strongest one being that of 775 AD.
During the March equinox of 2023, a strong easterly wind of ∼80 m s−1 appeared at an altitude of ∼82 km in the equatorial upper mesosphere, which is regarded as an enhancement of the mesopause semi‐annual oscillation. In this study, a new reanalysis data available up to 110 km was used to investigate its momentum budget.
This short article highlights unsolved problems of magnetic reconnection in collisionless plasma. Advanced in-situ plasma measurements and simulations have enabled scientists to gain a novel understanding of magnetic reconnection. Nevertheless, outstanding questions remain concerning the complex dynamics and structures in the diffusion region, cross-scale and regional couplings, the onset of magnetic reconnection, and the details of particle energization.
One of the most striking manifestations of orderly behavior emerging out of complex interactions in any astrophysical system is the 11 yr cycle of sunspots. However, direct sunspot observations and reconstructions of long-term solar activity clearly exhibit amplitude fluctuations beyond the decadal timescale, which may be termed as supradecadal modulation.
Context. The localised formation of planetesimals can be triggered with the help of streaming instability when the local pebble density is high. This can happen at various locations in the disc, and it leads to the formation of local planetesimal rings. The planetesimals in these rings subsequently grow from mutual collisions and by pebble accretion. Aims.
Launched in 2003, the European Space Agency’s Mars Express (MEX) has been orbiting Mars for 20 years and its instruments have performed continuous monitoring of the conditions in the Martian atmosphere, providing one of the most complete datasets of atmospheric parameters ever collected for Mars.
Context. Whether the Sun is an ordinary G-type star is still an open scientific question. Stellar surveys by Kepler and TESS, however, have revealed that Sun-like stars tend to show much stronger flare activity than the Sun. Aims. This study aims to reassess observed flare and spot activity of Sun-like Kepler stars by fine-tuning the criteria for a more robust definition of Sun-like conditions and better comparability between the current Sun and Sun-like stars. Methods.
From late October to early November 2003, one of the strongest recorded geomagnetic storms occurred due to heightened solar activity. Three ground‐level enhancement events (GLEs) took place during this period, GLE 65, 66, and 67, known as the Halloween events.
Plasma high-speed jets are common in Earth’s magnetosheath, and they significantly perturb the magnetosheath and affect the magnetosphere. The space environment of Mercury, characterized by the bow shock, magnetosheath, and magnetosphere, shares many similarities with that of Earth, so high-speed jets may also be formed in Mercury’s magnetosheath. Here we examine the formation of magnetosheath jets using a three-dimensional global hybrid simulation.
