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 emission of volatiles from the surface and subsurface of planetary bodies can provide fundamental knowledge concerning their formation, evolution, and structure. There are a variety of physical processes that shape the structural, kinematic and thermal behavior of the released material.
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.
With current observational methods it is not possible to directly measure the magnetic field in the solar corona with sufficient accuracy. Therefore, coronal magnetic field models have to rely on extrapolation methods using photospheric magnetograms as boundary conditions.
Context. Detailed shape modeling is a fundamental task in the context of small body exploration aimed at supporting scientific research and mission operations. The neural implicit method (NIM) is a novel deep learning technique that models the shapes of small bodies from multi-view optical images.
The quiet Sun corona and coronal holes, as seen in the extreme ultraviolet (EUV), host a variety of phenomena that operate over a range of spatial and temporal scales. Dynamic brightenings and jets of at most a few megameters appear to evolve on minute timescales. Coronal structures larger than tens of Mm evolve on much longer, hour timescales.
In this work, we used multiple ground‐based and space‐borne instruments, and we studied the ionospheric, thermospheric, magnetic and electrodynamic responses to the annular eclipse of 14 October 2023, that affected both North and South America. Based on the vertical total electron content (VTEC) maps and Swarm data sets, we observed a strong eclipse impact on the ionosphere with a 40% TEC depletion recorded at midlatitudes, likely induced by the lack of photoionization.
Three-dimensional direct numerical simulations are implemented to investigate the energy cascade rate in compressible isothermal magnetohydrodynamic turbulence. Utilizing an exact law derived from the Kármán–Howarth equation, we examine the contributions of flux and nonflux terms to the cascade rate across a broad range of sonic and Alfvénic Mach numbers, from subsonic to supersonic regimes and with varying mean magnetic fields.
To model the temperature evolution of optically thin astrophysical environments at MHD scales, radiative and collisional cooling rates are typically either pretabulated or fit into a functional form and then input into MHD codes as a radiative loss function. Thermal balance requires estimates of the analogous heating rates, which are harder to calculate, and due to uncertainties in the underlying dissipative heating processes these rates are often simply parameterized.
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.
