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The Intermittency of Turbulence in Magneto-Hydodynamical Simulations and in the Cosmos

Falgarone, Edith; Hily-Blant, Pierre; Lesaffre, Pierre

Turbulent dissipation is a central issue in the star and galaxy formation process. Its fundamental property of space-time intermittency, well characterised in incompressible laboratory experiments, remains elusive in cosmic turbulence. Progress requires the combination of state-of-the-art modelling, numerical simulations and observations. The powe…

The ap Prediction Tool Implemented by the A.Ne.Mo.S./NKUA Group

Mavromichalaki, Helen; Livada, Maria; Stassinakis, Argyris +4 more

A novel tool utilizing machine learning techniques was designed to forecast ap index values for the next three consecutive days (24 values). The tool employs time series data from the 3 h ap index of solar cycles 23 and 24 to train the Long Short-Term Memory (LSTM) model, predicting ap index values for the next 72 h at three-hour intervals. During…

Energy Dependence of Solar Energetic Protons and Their Origin in Solar Cycles 23 and 24

Miteva, Rositsa; Dechev, Momchil; Samwel, Susan W.

The study presents the compilation of a comprehensive catalog of solar energetic protons (SEPs) in solar cycles (SCs) 23 and 24 (1996–2019) in 10 energy channels from about 20 to 100 MeV based on data from the Energetic and Relativistic Nuclei and Electron (ERNE) instrument aboard Solar and Heliospheric Observatory (SOHO). For comparison, we added…

Parameter Study of Geoeffective Active Regions

Veronig, Astrid; Nedal, Mohamed; Pötzi, Werner +1 more

Geomagnetic storms (GSs) are major disturbances in the terrestrial atmosphere caused by the reconnection process between the incoming plasma ejecta in the solar wind and the planetary magnetosphere. The strongest GSs can lead to auroral displays even at lower latitudes, and cause both satellite and ground-based infrastructure malfunctions. The ear…

The Sun and Space Weather

Gopalswamy, Nat

The explosion of space weather research since the early 1990s has been partly fueled by the unprecedented, uniform, and extended observations of solar disturbances from space- and ground-based instruments. Coronal mass ejections (CMEs) from closed magnetic field regions and high-speed streams (HSS) from open-field regions on the Sun account for mo…

Twelve-Year Cycle in the Cloud Top Winds Derived from VMC/Venus Express and UVI/Akatsuki Imaging

Titov, Dmitrij V.; Ignatiev, Nikolay I.; Khatuntsev, Igor V. +3 more

We present joint analysis of the UV (365 nm) images captured by the cameras on board ESA's Venus Express and JAXA's Akatsuki spacecraft. These observations enabled almost continuous characterization of the cloud top circulation over the longest period of time so far (2006-2021). More than 46,000 wind vectors were derived from tracking the UV cloud…

From Atmospheric Evolution to the Search of Species of Astrobiological Interest in the Solar System—Case Studies Using the Planetary Spectrum Generator

Machado, Pedro; Ribeiro, José; Dias, João A.

The study of minor chemical species in terrestrial planets' atmospheres can teach us about the chemistry, dynamics and evolution of the atmospheres through time. Phosphine or methane on terrestrial planets are potential biosignatures, such that their detection may signify the presence of life on a planet. Therefore, the search for these species in…

Venus' Cloud-Tracked Winds Using Ground- and Space-Based Observations with TNG/NICS and VEx/VIRTIS

Machado, Pedro; Peralta, Javier; Silva, José E. +3 more

Characterizing the wind speeds of Venus and their variability at multiple vertical levels is essential for a better understanding of the atmospheric superrotation, constraining the role of large-scale planetary waves in the maintenance of this superrotation, and in studying how the wind field affects clouds' distribution. Here, we present cloud-tr…

Venus Atmospheric Dynamics at Two Altitudes: Akatsuki and Venus Express Cloud Tracking, Ground-Based Doppler Observations and Comparison with Modelling

Widemann, Thomas; Machado, Pedro; Peralta, Javier +6 more

Winds in the Lower Cloud Level on the Nightside of Venus from VIRTIS-M (Venus Express) 1.74 µm Images

Khatuntsev, Igor V.; Patsaeva, Marina V.; Zasova, Ludmila V. +2 more