Hydromagnetic dynamos at the low Ekman and magnetic Prandtl numbers

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F16%3A00472505" target="_blank" >RIV/67985530:_____/16:00472505 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1515/congeo-2016-0014" target="_blank" >http://dx.doi.org/10.1515/congeo-2016-0014</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1515/congeo-2016-0014" target="_blank" >10.1515/congeo-2016-0014</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Hydromagnetic dynamos at the low Ekman and magnetic Prandtl numbers

Popis výsledku v původním jazyce

Hydromagnetic dynamos are numerically investigated at low Prandtl, Ekman and magnetic Prandtl numbers using the PARODY dynamo code. In all the investigated cases, the generated magnetic fields are dominantly-dipolar. Convection is small-scale and columnar, while the magnetic field maintains its large-scale structure. In this study the generated magnetic field never becomes weak in the polar regions, neither at large magnetic Prandtl numbers (when the magnetic diffusion is weak), nor at low magnetic Prandtl numbers (when the magnetic diffusion is strong), which is a completely different situation to that observed in previous studies. As magnetic fields never become weak in the polar regions, then the magnetic field is always regenerated in the tangent cylinder. At both values of the magnetic Prandtl number, strong polar magnetic upwellings and weaker equatorial upwellings are observed. An occurrence of polar magnetic upwellings is coupled with a regenaration of magnetic fields inside the tangent cylinder and then with a not weakened intensity of magnetic fields in the polar regions. These new results indicate that inertia and viscosity are probably negligible at low Ekman numbers.

Název v anglickém jazyce

Hydromagnetic dynamos at the low Ekman and magnetic Prandtl numbers

Popis výsledku anglicky

Hydromagnetic dynamos are numerically investigated at low Prandtl, Ekman and magnetic Prandtl numbers using the PARODY dynamo code. In all the investigated cases, the generated magnetic fields are dominantly-dipolar. Convection is small-scale and columnar, while the magnetic field maintains its large-scale structure. In this study the generated magnetic field never becomes weak in the polar regions, neither at large magnetic Prandtl numbers (when the magnetic diffusion is weak), nor at low magnetic Prandtl numbers (when the magnetic diffusion is strong), which is a completely different situation to that observed in previous studies. As magnetic fields never become weak in the polar regions, then the magnetic field is always regenerated in the tangent cylinder. At both values of the magnetic Prandtl number, strong polar magnetic upwellings and weaker equatorial upwellings are observed. An occurrence of polar magnetic upwellings is coupled with a regenaration of magnetic fields inside the tangent cylinder and then with a not weakened intensity of magnetic fields in the polar regions. These new results indicate that inertia and viscosity are probably negligible at low Ekman numbers.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

DE - Zemský magnetismus, geodesie, geografie

OECD FORD obor

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Projekt

<a href="/cs/project/LG13042" target="_blank" >LG13042: Podpora účasti v řídících strukturách Mezinárodní asociace pro geomagnetizmus a aeronomii (IAGA)</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Contributions to Geophysics & Geodesy

ISSN

1335-2806

e-ISSN

—

Svazek periodika

46

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

SK - Slovenská republika

Počet stran výsledku

24

Strana od-do

221-244

Kód UT WoS článku

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EID výsledku v databázi Scopus

2-s2.0-85011596002