Magnetic and velocity fields in a dynamo operating at extremely small Ekman and magnetic Prandtl numbers

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F17%3A00486241" target="_blank" >RIV/67985530:_____/17:00486241 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1515/congeo-2017-0014" target="_blank" >http://dx.doi.org/10.1515/congeo-2017-0014</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1515/congeo-2017-0014" target="_blank" >10.1515/congeo-2017-0014</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Magnetic and velocity fields in a dynamo operating at extremely small Ekman and magnetic Prandtl numbers

Popis výsledku v původním jazyce

Numerical simulations of the geodynamo are becoming more realistic becausenof advances in computer technology. Here, the geodynamo model is investigated numerically at the extremely low Ekman and magnetic Prandtl numbers using the PARODY dynamo code. These parameters are more realistic than those used in previous numerical studies of the geodynamo. Our model is based on the Boussinesq approximation and the temperature gradient between upper and lower boundaries is a source of convection. This study attempts to answer the question how realistic the geodynamo models are. Numerical results show that our dynamo belongs to the strong-field dynamos. The generated magnetic field is dipolar and large-scale while convection is small-scale and sheet-like flows (plumes) are preferred to a columnar convection. Scales of magnetic and velocity fields are separated, which enables hydromagnetic dynamos to maintain the magnetic field atnthe low magnetic Prandtl numbers. The inner core rotation rate is lower than that innprevious geodynamo models. On the other hand, dimensional magnitudes of velocity and magnetic fields and those of the magnetic and viscous dissipation are larger than those expected in the Earth’s core due to our parameter range chosen.

Název v anglickém jazyce

Magnetic and velocity fields in a dynamo operating at extremely small Ekman and magnetic Prandtl numbers

Popis výsledku anglicky

Numerical simulations of the geodynamo are becoming more realistic becausenof advances in computer technology. Here, the geodynamo model is investigated numerically at the extremely low Ekman and magnetic Prandtl numbers using the PARODY dynamo code. These parameters are more realistic than those used in previous numerical studies of the geodynamo. Our model is based on the Boussinesq approximation and the temperature gradient between upper and lower boundaries is a source of convection. This study attempts to answer the question how realistic the geodynamo models are. Numerical results show that our dynamo belongs to the strong-field dynamos. The generated magnetic field is dipolar and large-scale while convection is small-scale and sheet-like flows (plumes) are preferred to a columnar convection. Scales of magnetic and velocity fields are separated, which enables hydromagnetic dynamos to maintain the magnetic field atnthe low magnetic Prandtl numbers. The inner core rotation rate is lower than that innprevious geodynamo models. On the other hand, dimensional magnitudes of velocity and magnetic fields and those of the magnetic and viscous dissipation are larger than those expected in the Earth’s core due to our parameter range chosen.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10508 - Physical geography

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

2017

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

47

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

SK - Slovenská republika

Počet stran výsledku

16

Strana od-do

261-276

Kód UT WoS článku

000425657300001

EID výsledku v databázi Scopus

2-s2.0-85042107260