Solar and astrophysical magnetohydrodynamics  Page description

Help  Print 
Back »
 

Details of project

  
Identifier
83133
Type K
Principal investigator Petrovay, Kristóf
Title in Hungarian Szoláris és asztrofizikai magnetohidrodinamika
Title in English Solar and astrophysical magnetohydrodynamics
Keywords in Hungarian Nap, naptevékenység, magnetohidrodinamika, turbulencia
Keywords in English Sun, solar activity, magnetohydrodynamics, turbulence
Discipline
Astronomy (Council of Physical Sciences)100 %
Ortelius classification: Astronomy
Panel Physics
Department or equivalent Department of Astronomy (Eötvös Loránd University)
Participants Balázs, Miklós
Ballai, István
Erdélyi, Róbert
Forgácsné Dajka, Emese Zelmíra
Marschalkó, Gábor
Starting date 2011-07-01
Closing date 2015-06-30
Funding (in million HUF) 16.469
FTE (full time equivalent) 10.93
state closed project
Summary in Hungarian
Az Univerzum látható anyagának zöme többé-kevésbé ionizált gáz, azaz plazma alakjában van jelen, melyben belsõ áramlások folynak. A plazma áramlása során a benne levõ szabad töltések mozgása elektromos áramot jelent, ez viszont mágneses teret kelt. A mágneses tér viszont visszahat a töltések mozgására, vagyis a közeg áramlására. A mágneses tér és az áramló vezetõ közegek kölcsönhatását a magnetohidrodinamika (elterjedt rövidítéssel: MHD) vizsgálja. Az asztrofizikai magnetohidrodinamika hagyományosan legfontosabb ''laboratóriuma'' a legközelebbi csillag, a Nap.
Az ELTE Csillagászati Tanszékén mûködõ szoláris MHD kutatócsoport hazánkban az egyetlen, e területen dolgozó elméleti mûhely. A hatvanas években alapított kutatócsoport munkája nemzetközi elismertségnek örvend. A csoport munkájának fõ pénzügyi bázisát hagyományosan egy OTKA kutatási pályázat jelenti. Jelen pályázat célja tehát, hogy 2011-tõl folytatólagosan biztosítsa a csoport munkájához szükséges anyagi hátteret.
Tervezett további kutatásaink három kulcskérdéshez kapcsolódnak:
(1) A naptevékenység eredete
(2) A napkorona fûtési mechanizmusa
(3) Asztrofizikai turbulencia és MHD
Summary
Much of the material of cosmic bodies is in the form of ionized gas or plasma. Flows in a plasma imply electric currents.
Currents have magnetic fields, which in turn have a feedback effect on the motions. The study of such flows in a compressible plasma is known as magnetohydrodynamics (MHD). The classic ''laboratory'' of astrophysical MHD, most accessible for detailed study, is the nearest star, our Sun.
The solar MHD research group at the Department of Astronomy of Eötvös University is the only theoretical research group in Hungary working in this field. Initiated in the 1960's, by now the group has become an internationally acknowledged team. The main source of funding for the group has traditionally been an OTKA research grant. In the last few years, OTKA support has also made it possible to slightly extend our field of research from purely solar studies towards other astrophysical applications of MHD. The aim of the present application is to ensure the continued availability of this principal source of funding for the further activity of the research group.
Our planned research will concentrate on problems related to three key issues in solar and astrophysical MHD:
(1) The origin of solar activity
(2) Mechanisms of coronal heating
(3) Astrophysical turbulence and MHD




 

Final report

  
Results in Hungarian
A pályázat az ELTE Csillagászati Tanszékén mûködő szoláris magnetohidrodinamikai kutatócsoport működésének fő finanszírozási forrása. Itt két fontos eredményünket emeljük ki a 2011--2015 évekből. A Nap fotoszférájában mindenfelé mutatkozó turbulens mágneses teret a tubulens vezető plazmában lokálisan fellépő kisléptékű dinamóhatásnak szokás tulajdonítani (egyébként kutatócsoportunk 1993-as javaslata nyomán). Analitikus eszközökkel és Monte Carlo szimulációkkal megmutattuk, hogy a mért mágneses fluxus felbontásfüggésére vonatkozó észlelési korlátok azt jelentik, hogy a turbulens mágneses energiaspektrum a 2-20 Mm mérettartományban csökkenő amplitúdót mutat, szemben a kisléptékű dinamó mai szimulációival. Ez arra utal, hogy a mai numerikus kísérletekkel ellentétben valós szoláris körülmények között a dinamóhatás nem az inerciális tartományban, csak a turbulencia integrális skáláján érvényesül, így esetleg fizikai mechanizmusa is alapvetően eltér a modellek működésétől. Nagy felbontású adatok alapján először mutattunk ki kifutó "penumbrális" hullámokat egy pórusban (penumbra nélküli napfoltban). Tekintettel a penumbra hiányára ez önmagában is megerősíti azt a közelmúltban javasolt értelmezést, miszerint a penumbrális hullámok valójában felfelé terjednek a mágneses tér mentén. Terjedésük felfelé egészen az alsó koronáig volt követhető. Ezzel a kromoszférában és koronában terjedő hullámok egy új, eddig figyelembe nem vett forrását tártuk fel.
Results in English
The project has been the principal source of funding for the solar and astrophysical magnetohydrodynamics research group at the Department of Astronomy of Eötvös University. In this summary we just mention two selected results of our research. The ubiquitous turbulent magnetic fields in the solar photosphere are usually explained (following a widely cited proposal by our research team back in 1993) by a local small-scale dynamo mechanism. By analytical means and Monte Carlo simulations we showed that observational constraints on the resolution dependence of the magnetic flux detected imply that the turbulent magnetic energy spectrum must be a decreasing function of the wave number in the range 2-20 Mm, at odds with current numerical simulations. We suggest that the small-scale dynamo operates on the integral scale, rather than inertial scale, of turbulence and its physical mechanism may also differ from the mechanism at work in current simulations. Using high resolution observational space data we detected running penumbral waves (RPWs) in a solar pore for the first time. Recent research suggests that RPWs are upwardly propagating field-aligned waves (UPWs). Our observation corroborates this interpretation due to the lack of a penumbra. We were able to follow the propagation of these UPWs up to the transition region and low corona. This is a new, yet unconsidered source of wave energy within the solar chromosphere and low corona.
Full text https://www.otka-palyazat.hu/download.php?type=zarobeszamolo&projektid=83133
Decision
Yes





 

List of publications

  
Belucz B., Dikpati M., Forgács-Dajka E.: A Babcock-Leighton solar dynamo model with multi-cellular meridional circulation in advection- and diffusion-dominated regimes, Astrophys. J. 806, 169, 2015
Freij N., Scullion E. M., Nelson C. J., Mumford S., Wedemeyer S., Erdélyi R.: The detection of upwardly propagating waves channeling energy from the chromosphere to the low corona, Astrophys. J. 791, 61, 2014
Nelson C. J., Scullion E. M., Doyle J. G., Freij N., Erdélyi R.: Small-scale structuring of Ellerman bombs at the solar limb, Astrophys. J. 798, 19, 2015
Mumford S. J., Fedun V., Erdélyi R.: Generation of magnetohydrodynamic waves in low solar atmospheric flux tubes by photospheric motions, Astrophys. J. 799, 6, 2015
Guo Y., Erdélyi R., Srivastava A. K., Hao Q., Cheng X., Chen P. F., Ding M. D., Dwivedi B. N.: Magnetohydrodynamic seismology of a coronal loop system by the first two modes of standing kink waves, Astrophys. J. 799, 151, 2015
Korsós M. B., Ludmány A., Erdélyi R., Baranyi T.: On flare predictability based on sunspot group evolution, Astrophys. J. 802, L21, 2015
Mumford S. J., Erdélyi R.: Photospheric logarithmic velocity spirals as MHD wave generation mechanisms, Mon. Not. Roy. Astr. Soc. 449, 1679-1685, 2015
Grant S. D. T., Jess D. B., Moreels M. G., Morton R. J., Christian D. J., Giagkiozis I., Verth G., Fedun V., Keys P. H., Van Doorsselaere T., Erdélyi R.: Wave damping observed in upwardly propagating sausage-mode oscillations contained within a magnetic pore, Astrophys. J. 806, 132, 2015
Marschalkó G., Petrovay K.: Turbulent magnetic energy spectrum and the cancellation function of solar photospheric magnetic fields, Astr.Nachr. 334, 952-955, 2013
Nagy M., Petrovay K.: Oscillator Models of the Solar Cycle and the Waldmeier Effect, Astr.Nachr. 334, 964-967, 2013
Murawski K., Ballai I., Srivastava A. K., Lee D.: Three-dimensional numerical simulation of magnetohydrodynamic-gravity waves and vortices in the solar atmosphere, Mon Not. Roy. Astr. Soc. 436, 1268-1277 (2013), 2013
Gent F. A., Fedun V., Mumford S. J., Erdélyi R.: Magnetohydrostatic equilibrium - I. Three-dimensional open magnetic flux tube in the stratified solar atmosphere, Mon Not. Roy. Astr. Soc. 435, 689-697, 2013
Kuridze D., Verth G., Mathioudakis M., Erdélyi R., Jess D. B., Morton R. J., Christian D. J., Keenan, F. P.: Characteristics of Transverse Waves in Chromospheric Mottles, Astrophys. J. 779, 82, 2013
Nelson C. J., Shelyag S., Mathioudakis M., Doyle J. G., Madjarska M. S., Uitenbroek H., Erdélyi R.: Ellerman Bombs - Evidence for Magnetic Reconnection in the Lower Solar Atmosphere, Astrophys. J. 779, 125, 2013
Hillier A., Morton R. J., Erdélyi R.: A Statistical Study of Transverse Oscillations in a Quiescent Prominence, Astrophys. J. 779, L16, 2013
He J., Xu S., Ruderman M. S., Erdélyi R.: State Transition Induced by Self-Steepening and Self Phase-Modulation, Chinese Phys. Lett. 31, 010502, 2014
Erdélyi R., Hague A., Nelson C. J.: Effects of Stratification and Flows on P1/P2 Ratios and Anti-node Shifts Within Closed Loop Structures, Solar Phys. 289, 167-182, 2014
Dorotovic I., Erdélyi R., Freij N., Karlovský V., Márquez I.: Standing sausage waves in photospheric magnetic waveguides, Astron. Astrophys. 563, A12, 2014
Morton R. J., Verth G., Hillier A., Erdélyi R.: The Generation and Damping of Propagating MHD Kink Waves in the Solar Atmosphere, Astrophys. J. 784, 29, 10 pp. (2014), 2014
He J., Wang L., Li L., Porsezian K., Erdélyi R.: Few-cycle optical rogue waves: Complex modified Korteweg-de Vries equation, Phys. Rev. E 89, 062917, 2014
Gent F. A., Fedun V., Erdélyi R.: Magnetohydrostatic Equilibrium. II. Three-dimensional Multiple Open Magnetic Flux Tubes in the Stratified Solar Atmosphere, Astrophys. J. 789, 42, 2014
Pardi A., Ballai I., Marcu A., Orza B.: Sausage Mode Propagation in a Thick Magnetic Flux Tube, Solar Phys. 289, 1203-1214, 2014
Balázs L. G., Gyenge N., Korsós M. B., Baranyi T., Forgács-Dajka E., Ballai I.: Statistical relationship between the succeeding solar flares detected by the RHESSI satellite, Mon Not. Roy. Astr. Soc. 441, 1157-1165, 2014
Lopes I., Passos D., Nagy M., Petrovay K.: Oscillator models of the solar cycle. Towards the development of inversion methods, Space Sci. Rev. 186, 535-559, 2014
Petrie G. J. D., Petrovay K., Schatten, K.: Solar polar fields and the 22-year activity cycle: Observations and models, Space Sci. Revi. 186, 325-357, 2014
Ballai I., Jess D.B., Douglas M.: TRACE observations of driven loop oscillations, Astron. Astrophys. 534, A13, 2011
Kumar P., Ablishek K. Srivastava A.K., Filippov B., Erdélyi R., Uddin W.: Multiwavelength observations of a failed flux rope in the eruption and associated M-class flare from NOAA AR 11045, Solar Phys. 272, 301-317, 2011
Morton R. J., Verth G., McLaughlin J.A., Erdélyi R.: Determination of sub-resolution structure of a jet by solar magnetoseismology, Astrophys. J. 744, 5, 2012
Luna-Cardozo M., Verth G., Erdélyi R.: Longitudinal oscillations in density stratified and expanding solar waveguides, Astrophys. J. 748, 110, 2012
McLaughlin J.A., Verth G., Fedun V., Erdélyi, R.: Generation of quasi-periodic waves and flows in the solar atmosphere by oscillatory reconnection, Astrophys. J. 749, 30, 2012
Kuridze D., Morton R. J., Erdélyi R., Dorrian G.D., Mathioudakis M., Jess D. B., Keenan F.P.: Transverse oscillations in chromospheric mottles, Astrophys. J. 750, 51, 2012
Morton R.J., Srivastava A.K., Erdélyi R.: Observations of quasi-periodic phenomena associated with a large blowout solar jet, Astron. Astrophys. 542, A70, 2012
Luna-Cardozo M., Verth G., Erdélyi R.: Magneto-seismology of solar atmospheric loops by means of longitudinal oscillations, IAU Symposium 286, 437-440, 2012
Orza B., Ballai I., Jain R., Murawski K.: The effect of the environment on the P1/P2 period ratio for kink oscillations of coronal loops, Astron. Astrophys. 537, A41, 2012
Ballai I., Orza B.: Transverse kink oscillations of expanding coronal loops, Astron. Astrophys. 545, A118, 2012
Karak B. B., Petrovay K.: On the Compatibility of a Flux Transport Dynamo with a Fast Tachocline Scenario, Solar Phys. 282, 321-334, 2013
Tian C., Petrovay K.: Structures in compressible magnetoconvection and the nature of umbral dots, Astron. Astrophys. 551, A92, 2013
Vigeesh G., Fedun V., Hasan S. S., Erdélyi R.: Three-dimensional Simulations of Magnetohydrodynamic Waves in Magnetized Solar Atmosphere, Astrophys. J. 755, 18, 2012
Morton R. J., Verth G., Jess, D. B., Kuridze D., Ruderman M. S. Mathioudakis M., Erdélyi R.: Observations of ubiquitous compressive waves in the Sun's chromosphere, Nature Communications 3, 1315, 2012
Srivastava A. K., Erdélyi R., Murawski K., Kumar P.: Multiwavelength Observations of Supersonic Plasma Blob Triggered by Reconnection-Generated Velocity Pulse in AR10808, Solar Phys. 281 729-747, 2012
Srivastava A. K., Erdélyi R., Tripathi D., Fedun V., Joshi N. C., Kashyap P.: Observational Evidence of Sausage-pinch Instability in Solar Corona by SDO/AIA, Astrophys. J. 765, L42, 2013
Nelson C. J., Doyle J. G., Erdélyi R., Huang Z., Madjarska M. S., Mathioudakis M., Mumford S. J., Reardon K.: Statistical Analysis of Small Ellerman Bomb Events, Solar Phys. 283, 307-323, 2013
Morton R. J., Verth G., Fedun V., Shelyag S., Erdélyi R.: Evidence for the Photospheric Excitation of Incompressible Chromospheric Waves, Astrophys. J. 768, 17, 2013
Mathioudakis M., Jess D. B., Erdélyi R.: Alfvén Waves in the Solar Atmosphere. From Theory to Observations, Space Sci. Rev. 175, 1-27, 2013
Karak BB, Petrovay K: On the Compatibility of a Flux Transport Dynamo with a Fast Tachocline Scenario, SOL PHYS 282: (2) 321-334, 2013
Tian C, Petrovay K: Structures in compressible magnetoconvection and the nature of umbral dots, ASTRON ASTROPHYS 551: , 2013



Back »