Department of Astronomy (Eötvös Loránd University)
Participants
Ballai, István Erdélyi, Róbert Forgácsné Dajka, Emese Zelmíra Kerekes, Andrea Marik, Dániel Pintér, Balázs
Starting date
2003-01-01
Closing date
2007-12-31
Funding (in million HUF)
8.885
FTE (full time equivalent)
0.00
state
closed project
Final report
Results in Hungarian
A pályázat az ELTE Csillagászati Tanszékén működő szoláris magneto-hidrodinamikai kutatócsoport működésének fő finanszírozási forrása. Itt két fontos eredményünket emeljük ki a 2003--2006 évekből.
A világon elsőként kifejlesztett gyors tachoklínamodellünket (ld. a T032462 OTKA pályázat zárójelentését) továbbfejlesztettük és realisztikusabbá tettük. A tachoklína a napbelső egy fontos rétege, mely mai elképzelésünk szerint a dinamó székhelye. Modellünkben a tachoklína eléggé turbulens ahhoz, hogy a Nap oszcilláló mágneses tere azt egészében áthassa, s így meghatározza annak
dinamikáját.
Új mechanizmust javasoltunk a Nap kromoszférájában látható szpikulák eredetére. A mechanizmus lényege. hogy a mágneses hálózat vékony erővonalcsövei felfelé terelik az ötperces oszcillációkat.
Results in English
The project has been the principal source of funding for the solar and astrophysical research group at the Department of Astronomy of Eötvös University. In this summary we just mention two key results of our research.
We have further developed our model for the so-called fast solar tachocline. The tachocline is an important layer in the solar interior, thought to be the seat of the dynamo. In our model, this layer is assumed to be turbulent enough to allow penetration of the overlying oscillatory magnetic field into much of the tachocline, controlling its dynamics.
A new mechanism was proposed for the origin of spicules in the solar chromomosphere. The mechanism is based on upward channeling of photospheric 5-minute oscillations by the tilted magnetic network tubes.
De Pontieu B; Erdélyi R; de Wijn AG: Intensity Oscillations in the Upper Transition Region above Active Region Plage, Astrophys J 595 L63-L66, 2003
Terra-Homem M; Erdélyi R; Ballai I.: Linear and non-linear MHD wave propagation in steady-state magnetic cylinders, Solar Phys 217, 199-223, 2003
Forgács-Dajka E: Dynamics of the fast solar tachocline II Migrating field, Astron Astrophys 413 1143-1151, 2004
Petrovay K; Chatterjee P; Choudhuri A: Helical Magnetic Fields in Solar Active Regions: Theory vs. Observations, Publ Astron Dept Eötvös Univ 17 5-14, 2006
Borkovits T; Forgács-Dajka E; Regály Zs: Tidal and rotational effects in the perturbations of hierarchical triple stellar systems I Numerical model and a test application for Algol, Astron Astrophys 426 951-961, 2004
Forgács-Dajka E; Major B; Borkovits T: Long-term variation in distribution of sunspot groups, Astron Astrophys 424 311-315, 2004
Forgács-Dajka E: Structure of the solar tachocline: confrontation of theoretical models with SOHO/MDI helioseismic constraints, Publ Astron Dept Eötvös Univ 14 177-185, 2004
Erdélyi R: Heating in the Solar Atmosphere, Astron & Geophys 45 434-437, 2004
De Pontieu B; Erdélyi R; James S P: Solar Spicules Driven by Leakage into the Chromosphere of Photospheric Oscillations and Flows, Nature 430 536-539, 2004
Erdélyi R; James SP: Can ion-neutral damping help to form spicules? II Random Driver, Astron & Astrophys 427 1055-1064, 2004
Mendoza-Briceño CA; Erdélyi R; Sigalotti D: The Effects of Stratification on Oscillating Coronal Loops, Astrophys J 605 493-502, 2004
Miteva R; Zhelyazkov I; Erdélyi R: Hall-magnetohydrodynamic surface waves in solar wind flow-structures, New J Phys 6 14 (18 pages), 2004
Pelinovsky E; Talipova T; Ruderman MS; Erdélyi R: Freak Waves Described by the Korteweg - de Vries Equation, Applied Mathematics and Mechanics 6 3-16, 2004
Ruderman MS; Brevdo L; Erdélyi R: Kelvin-Helmholtz Instabilities of, and Signalling in, an Inviscid Fluid - Viscous Fluid Configuration, Proc Roy Soc 460 847-874, 2004
Terra-Homem M; Erdélyi R: Absolute and Convective Instabilities in Open Shear Layers II. Magnetohydrodynamic Equilibrium, Astron & Astrophys 413 7-15, 2004
Grimshaw R; Pelinovsky J; Talipova T; Ruderman MS; Erdélyi: Short-lived Large-amplitude Pulses in the Nonlinear Long-wave Model Described by the Modified Korteweg - de Vries Equation, Studies in Applied Math 114 189-210, 2005
Ballai I; Marcu A: The effect of anisotropy on the propagation of linear compressional waves in magnetic flux tubes: Applications to astrophysical plasmas, Astron Astrophys 415, 691-703, 2004
Ballai I: On dissipative effects in solar prominences, Astron Astrophys 410, L17-L19, 2003
Erdélyi R; Kerekes A; Mole N: Influence of random magnetic field on solar global oscillations: The incompressible f-mode, Astron Astrophys 431 1083-1088, 2005
Mendoza-Briceño CA; Di G. Sigalotti L; Erdélyi R: Catastrophic Cooling of Impulsively Heated Coronal Loops, Astrophys J 624, 1080-1092, 2005
Taroyan Y; Erdélyi R; Doyle JG; Bradshaw SJ: Footpoint excitation of standing acoustic waves in coronal loops, Astron Astrophys 438, 713-720, 2005
Ballai I; Erdélyi R; Pintér B: On the Nature of Coronal EIT Waves, Astrophys J 633, L145-L148, 2005
De Pontieu B; Erdélyi R; De Moortel I: How to Channel Photospheric Oscillations into the Corona, Astrophys J 624, L61-L64, 2005
Chatterjee P; Choudhuri A.; Petrovay K.: Development of twist in an emerging magnetic flux tube by poloidal field accretion, Astron Astrophys 449 781-789, 2006
Taroyan Y; Erdélyi R; Doyle JG; Bradshaw SJ: Analysis of power spectra of Doppler shift time series as a diagnostic tool for quiescent coronal loops, Astron Astrophys 462 331-340, 2006
Petrovay K; Erdélyi R; Thompson M J: The Effect of Abnormal Granulation on Acoustic Wave Travel Times and Mode Frequencies, Solar Phys, in press, 2007
Chatterjee P; Choudhuri A; Petrovay K: A Theoretical Model for the Magnetic Helicity of Solar Active Regions, Adv. Space Res., in press, 2007
Forgács-Dajka E; Borkovits T: Searching for mid-term variations in different aspects of solar activity - looking for probable common origins and studying temporal variations of magnetic polarities, Mon Not RAS 374, 282-291, 2007
Marschalkó G: Superdiffusion in molecular clouds, IAU Symp 27, 162, 2006
Simpson D; Ruderman M S; Erdélyi R: Absolute and convective instabilities of parallel propagating circularly polarized Alfvén waves: numerical results, Astron Astrophys 452, 641-646, 2006
Marschalkó G: Superdiffusion in molecular clouds, Publ Astr Dept Eötvös Univ 17, 179-185, 2006
Erdélyi R; Carter, B. K.: Wave propagation in incompressible MHD wave guides: the twisted magnetic annulus, Astron Astrophys 455 361-370, 2006
Mendoza-Briceño CA; Erdélyi R: Intermittent Coronal Loop Oscillations by Random Energy Releases, Astrophys J 648 722-731, 2006
Erdélyi R.; Fedun V: Sausage MHD Waves in Incompressible Flux Tubes with Twisted Magnetic Fields, Solar Phys 238, 41-59, 2006
Shelyag S; Erdélyi R; Thompson M J: Forward Modeling of Acoustic Wave Propagation in the Quiet Solar Subphotosphere, Astrophys J 651 576-583, 2006
Erdélyi R; Verth G: The effect of density stratification on the amplitude profile of transversal coronal loop oscillations, Astron Astrophys 462 743-751, 2006
Marcu A; Ballai I; Pintér B: Magnetohydrodynamic modes in a periodic magnetic steady state medium, Astron Astrophys 449 1193-1202, 2006
