ELFT HÍRADÓ

[ilka AT konkoly.hu (Kalman Belane)]

                          Meghivo
     
      az MTA Csillagaszati Kutatointezete Szeminariumara 
                        

Eloado: Petrovay Kristof
        (ELTE Csillagaszati tsz.)

Cim:              WHAT MAKES THE SUN TICK?
               (The Origin of the Solar Cycle)

In contrast to the situation with the geodynamo, no breakthrough has been made
in the solar dynamo problem for decades. Since the appearance of mean-field
electrodynamics in the 1960's, the only really significant advance was in the
field of flux tube theory and flux emergence calculations. These new results,
together with helioseismic evidence, have led to the realization that the
toroidal magnetic flux giving rise to activity phenomena must be stored and
presumably generated below the convection zone proper, in what I will call the
DOT (Dynamo-Overshoot-Tachoclyne) layer. The only segment of the problem we 
can
claim to basically understand is the transport of flux from this layer to the
surface. On the other hand, as reliable models for the DOT layer do not exist
we are clueless concerning the precise mechanisms responsible for
toroidal/poloidal flux conversion and for characteristic migration patterns
(extended butterfly diagram) and periodicities. Even the most basic result of
mean-field theory, the identification of the butterfly diagram with an
alpha-omega dynamo wave, has been questioned. This review therefore will
necessarily ask more questions than give answers. Some of these key questions
are 
  - Structure of the DOT layer
  - alpha-quenching and distributed dynamo 
  - High-latitude migration patterns and their interpretation 
  - The ultimate fate of emerged flux

Idopont: 2000. oktober 26. csutortok, 14 ora 
Helyszin: MTA Csillagaszati Kutatointezete eloadoterme
          Budapest, XII. Konkoly Thege u. 15/17.
  
                             
Ha a hallgatosagbol mindenki tud magyarul, akkor magyarul lesz megtartva az 
eloadas.


                                      Patkos Laszlo 
                                          s. k.