Zobrazeno 1 - 10
of 69
pro vyhledávání: '"Käpylä, Maarit J."'
In this study we present a compressible test-field method (CTFM) for computing $\alpha$ effect and turbulent magnetic diffusivity tensors, as well as those relevant for mean ponderomotive force and mass source, applied to the full MHD equations. We d
Externí odkaz:
http://arxiv.org/abs/2106.01107
Autor:
Warnecke, Jörn, Rheinhardt, Matthias, Viviani, Mariangela, Gent, Frederick, Tuomisto, Simo, Käpylä, Maarit J.
Publikováno v:
2021 ApJL 919 L13
The role of turbulent effects for dynamos in the Sun and stars continues to be debated. Mean-field (MF) theory provides a broadly used framework to connect these effects to fundamental magnetohydrodynamics. While inaccessible observationally, turbule
Externí odkaz:
http://arxiv.org/abs/2105.07708
In this study we present a dynamical agent-based model to investigate the interplay between the socio-economy of and SEIRS-type epidemic spreading over a geographical area, divided to smaller area districts and further to smallest area cells. The mod
Externí odkaz:
http://arxiv.org/abs/2105.06718
Publikováno v:
Parallel Computing, Volume 111, 2022, 102904
Modern compute nodes in high-performance computing provide a tremendous level of parallelism and processing power. However, as arithmetic performance has been observed to increase at a faster rate relative to memory and network bandwidths, optimizing
Externí odkaz:
http://arxiv.org/abs/2103.01597
Autor:
Väisälä, Miikka S., Pekkilä, Johannes, Käpylä, Maarit J., Rheinhardt, Matthias, Shang, Hsien, Krasnopolsky, Ruben
Magnetohydrodynamical (MHD) dynamos emerge in many different astrophysical situations where turbulence is present, but the interaction between large-scale (LSD) and small-scale dynamos (SSD) is not fully understood. We performed a systematic study of
Externí odkaz:
http://arxiv.org/abs/2012.08758
Publikováno v:
ApJ 910 110 (2021)
The magnetic activity of late-type stars is correlated with their rotation rates. Up to a certain limit, stars with smaller Rossby numbers, defined as the rotation period divided by the convective turnover time, have higher activity. A more detailed
Externí odkaz:
http://arxiv.org/abs/2007.00040
Autor:
Käpylä, Maarit J., Vizoso, Javier Álvarez, Rheinhardt, Matthias, Brandenburg, Axel, Singh, Nishant K.
Publikováno v:
Astrophys. J. 905, 179 (2020)
The possibility of explaining shear flow dynamos by a magnetic shear-current (MSC) effect is examined via numerical simulations. Our primary diagnostics is the determination of the turbulent magnetic diffusivity tensor $\boldsymbol{\eta}$. In our set
Externí odkaz:
http://arxiv.org/abs/2006.05661
One interpretation of the activity and magnetism of late-type stars is that these both intensify with decreasing Rossby number up to a saturation level, suggesting that stellar dynamos depend on both rotation and convective turbulence. Some studies h
Externí odkaz:
http://arxiv.org/abs/2003.08997
Autor:
Lehtinen, Jyri J., Käpylä, Maarit J., Hackman, Thomas, Kochukhov, Oleg, Willamo, Teemu, Marsden, Stephen C., Jeffers, Sandra V., Henry, Gregory W., Jetsu, Lauri
Publikováno v:
A&A 660, A141 (2022)
Previous studies have related surface temperature maps, obtained with the Doppler imaging (DI) technique, of LQ Hya with long-term photometry. We compare surface magnetic field maps, obtained with the Zeeman Doppler imaging (ZDI) technique, with cont
Externí odkaz:
http://arxiv.org/abs/1909.11028
Autor:
Cole-Kodikara, Elizabeth M., Käpylä, Maarit J., Lehtinen, Jyri J., Hackman, Thomas, Ilyin, Ilya V., Piskunov, Nikolai, Kochukhov, Oleg
Publikováno v:
A&A 629, A120 (2019)
Context. LQ Hya is one of the most frequently studied young solar analogue stars. Recently, it has been observed to show intriguing behaviour by analysing long-term photometry: during 2003--2009, a coherent spot structure migrating in the rotational
Externí odkaz:
http://arxiv.org/abs/1904.08713