Search Publications
Auroral kilometric radiation—The electron cyclotron maser paradigm
Treumann, R. A.; Baumjohann, Wolfgang
Auroral kilometric radiation (AKR) is the paradigm of intense radio emission from planetary magnetospheres. Being close to the electron gyro frequency and/or its lower harmonics, its observation indicates the non-thermal state of the source plasma. Emission is produced when the plasma enters a state of energetic excitation which results in deforma…
Subarcsecond Imaging of a Solar Active Region Filament With ALMA and IRIS
Heinzel, P.; Gunár, S.; Leenaarts, J. +4 more
Quiescent filaments appear as absorption features on the solar disk when observed in chromospheric lines and at continuum wavelengths in the millimeter (mm) range. Active region (AR) filaments are their small-scale, low-altitude analogues, but they could not be resolved in previous mm observations. This spectral diagnostic can provide insight into…
Solar Energetic Particle Time Series Analysis with Python
Dresing, Nina; Vainio, Rami; Price, Daniel J. +6 more
Solar Energetic Particles (SEPs) are charged particles accelerated within the solar atmosphere or the interplanetary space by explosive phenomena such as solar flares or Coronal Mass Ejections (CMEs). Once injected into the interplanetary space, they can propagate towards Earth, causing space weather related phenomena. For their analysis, interpla…
Uniting the Sun's Hale magnetic cycle and "extended solar cycle" paradigms
McIntosh, Scott W.; Leamon, Robert J.; Scherrer, Philip H. +1 more
Through meticulous daily observation of the Sun's large-scale magnetic field the Wilcox Solar Observatory (WSO) has catalogued two magnetic (Hale) cycles of solar activity. Those two (∼22-year long) Hale cycles have yielded four (∼11-year long) sunspot cycles (numbers 21 through 24). Recent research has highlighted the persistence of the "Extended…
Magnetospheric responses to solar wind Pc5 density fluctuations: Results from 2D hybrid Vlasov simulation
Alho, Markku; Johlander, Andreas; Pfau-Kempf, Yann +17 more
Ultra-low frequency (ULF) waves are routinely observed in Earth's dayside magnetosphere. Here we investigate the influence of externally-driven density variations in the near-Earth space in the ULF regime using global 2D simulations performed with the hybrid-Vlasov model Vlasiator. With the new time-varying boundary setup, we introduce a monochrom…
Direct Evidence of Magnetic Reconnection Onset via the Tearing Instability
Verscharen, Daniel; Walsh, Andrew P.; Forsyth, Colin +4 more
Magnetic reconnection is a sporadic process responsible for energy release in space and laboratory plasmas. It is believed that the tearing mode instability may be responsible for the onset of reconnection in the magnetotail. However, due to its elusive nature, there is an absence of in-situ observations of the tearing instability prior to magneti…
The quiet sun at mm wavelengths as seen by ALMA
Brajša, Roman; Bastian, T. S.; Alissandrakis, Costas E.
Solar observations at sub-mm, mm and cm wavelengths offer a straightforward diagnostic of physical conditions in the solar atmosphere because they yield measurement of brightness temperature which, for optically thick features, equals intrinsic temperature - much unlike solar diagnostics in other spectral ranges. The Atacama Large Millimeter and s…
Multi-Spacecraft Observations of Fluctuations Occurring Along the Dusk Flank Magnetopause, and Testing the Connection to an Observed Ionospheric Bead
Wing, Simon; Petrinec, Steven M.; Zhang, Yongliang +1 more
During 2018 November 06, 11:30—18:00 UT, the MMS constellation, the Cluster set of spacecraft, and the Geotail spacecraft were all situated near the dusk flank magnetopause. Large scale fluctuations were observed by the available and operating science instruments at these various spacecraft (i.e., magnetic field, plasma moment, and energy flux mea…
Consolidation of the Gaia catalogue with Chinese Space Station Telescope astrometry
Lattanzi, M.; Busonero, D.; Cancelliere, R. +4 more
The issue of preservation and improvement of the Gaia catalogue throughout the next few decades is addressed. The goal of this paper is to evaluate the feasibility of astrometric parameter update, for objects already in the catalogue, by inclusion of new observations from other space missions, in particular CSST. The proposed approach consists in …
Daring to think of the impossible: The story of Vlasiator
Palmroth, Minna
Vlasiator is the world's first global Eulerian hybrid-Vlasov simulation code, going beyond magnetohydrodynamics in the solar wind—magnetosphere—ionosphere system. This paper gives the story of Vlasiator. An important enabler of Vlasiator is the rapid increase of computational resources over the last decade, but also the open-minded, courageous for…