Search Publications
A review of observed variability in the dayside ionosphere of Mars
Withers, Paul
Recent measurements by Mars Global Surveyor and Mars Express have greatly increased the number of observations of the martian dayside ionosphere available for study. Together with earlier measurements from the Viking era, these datasets have been used to investigate variations in well-known properties of the martian dayside ionosphere and to disco…
Driving major solar flares and eruptions: A review
Schrijver, Carolus J.
This review focuses on the processes that energize and trigger M- and X-class solar flares and associated flux-rope destabilizations. Numerical modeling of specific solar regions is hampered by uncertain coronal-field reconstructions and by poorly understood magnetic reconnection; these limitations result in uncertain estimates of field topology, …
Modelling and observations of photospheric magnetic helicity
Démoulin, P.; Pariat, E.
Mounting observational evidence of the emergence of twisted magnetic flux tubes through the photosphere have now been published. Such flux tubes, formed by the solar dynamo and transported through the convection zone, eventually reach the solar atmosphere. Their accumulation in the solar corona leads to flares and coronal mass ejections. Since rec…
Ion and electron superdiffusive transport in the interplanetary space
Zimbardo, Gaetano; Perri, Silvia
We study the propagation of energetic particles, accelerated by interplanetary shock waves, upstream of the shock. By using the appropriate propagator, we show that in the case of superdiffusive transport, the time profile of particles accelerated at a traveling planar shock is a power-law with slope 0<γ<1, at variance with the exponential p…
Blazar nuclei in radio-loud narrow-line Seyfert 1?
Maraschi, L.; Ghisellini, G.; Tavecchio, F. +3 more
It has been suggested that some radio-loud narrow-line Seyfert 1 contain relativistic jets, on the basis of their flat-spectrum radio nuclei and studies on variability. We present preliminary results of an ongoing investigation of the X-ray and multiwavelength properties of 5 radio-loud NLS1 based on archival data from Swift and XMM-Newton. Some s…
Surface elements and landing strategies for small bodies missions - Philae and beyond
Ulamec, Stephan; Biele, Jens
The investigation of small bodies, comets and asteroids, can contribute substantially to our understanding of the formation and history of the Solar System. In-situ observations by Landers play a prominent role in this field. The Rosetta Lander - Philae - is currently on its way to comet 67P/Churyumov-Gerasimenko. It will land in November 2014 and…
Solar irradiance forecast and far-side imaging
Haberreiter, M.; Fontenla, J. M.; Lindsey, C. +2 more
This paper presents a new approach to forecasting short-term Lyα solar irradiance variations due to the presence and evolution of magnetically heated regions in the Sun's outer atmosphere. This scheme is based on images of the solar disk at key wavelengths, currently Ca II K filtergrams, maps of backscattered solar Lyα from the interplanetary medi…
AKARI observations of the ISM in our Galaxy and nearby galaxies
Takahashi, H.; Onaka, T.; Kaneda, H. +1 more
With AKARI, we have systematically performed near- to far-infrared (NIR-FIR) observations of the interstellar medium (ISM) in our Galaxy and nearby galaxies as one of AKARI mission programs called ISMGN (ISM in our Galaxy and Nearby galaxies). Our scientific objective is to increase our knowledge on the properties of the ISM exposed to an extensiv…
Analyses of magnetic field structures for active region 10720 using a data-driven 3D MHD model
Liu, Yang; Wu, S. T.; Yurchyshyn, Vasyl +5 more
In order to understand solar eruptive events (flares and CMEs) we need to investigate the changes at the solar surface. Thus, we use a data-driven, three-dimensional magnetohydrodynamic (MHD) model to analyze a flare and coronal mass ejection productive active region, AR 10720 on January 15, 2005. The measured magnetic field from Big Bear Solar Ob…
Hybrid simulations of the O + ion escape from Venus: Influence of the solar wind density and the IMF x component
Kallio, E.; Janhunen, P.; Lammer, H. +6 more
As an initial effort to study the evolution of the Venus atmosphere, the influence of the solar wind density and the interplanetary magnetic field (IMF) x component (the x-axis points from Venus towards the Sun) on the O + ion escape rate from Venus is investigated using a three-dimensional quasi-neutral hybrid (HYB-Venus) model. The HY…