||I am working as professor of space physics in
the Space Research
Group of the
Department of Physical
Sciences in the University of Oulu, Finland.
I conduct research in space physics, in particular in heliospheric and magnetospheric physics.
Most of my research deals with Space Climate, i.e., the study of
long-term changes in the Sun and its effects in the heliosphere (solar
wind and heliospheric magnetic field), and in the near-Earth space
(magnetosphere, ionosphere, atmosphere) and climate.
Some highlights: Bashful Ballerina
We have made interesting new findings about the solar/heliospheric
structure. The heliospheric current sheet (HCS) which separates the two
magnetic hemispheres has a wavy structure and is therefore often called
the ballerina skirt. Interestingly, HCS is systematically shifted or
displaced southwards from the solar heliographic equator during the
declining to minimum phase of the solar cycle.
We have amused ourselves with the following analogy:
It seems that, whenever her activity is fading, the solar Ballerina
becomes aware of her high flaring skirt and she tries to push it
downward. The Sun is therefore a Bashful Ballerina.
We have also found that the dominance of either of the two magnetic
hemispheres alternates with a period of about 3.2 years. This implies
that two subsequent tilts (deflections with respect ot the rotation
axis) of the heliospheric magnetic field (HMF) and are, on an average,
roughly directed in opposite longitudes. Thus, the solar magnetic field
has two active longitudes whose activity alternates ("flip-flops") three
times in an 10-year solar activity cycle. (Nowadays cycles are slightly
shorter and higher than, say 100 years ago).
Thinking these activations as "steps" of the Bashful Ballerina, we can say that she is dancing in waltz tempo !
In fact, recent studies have shown that this ratio of 3 between the
activity cycle and the flip-flop cycle is common for cool, sun-like
stars. Accordingly, there is a lot of waltzing in the Heavens by all
those Bashful Ballerinas!
You can read about this more, e.g., in the following publications:
Mursula, and T. Hiltula, Bashful ballerina: Southward shifted
heliospheric current sheet, Geophys. Res. Lett. 30 (22), p. SSC 2--1-4,
doi: 10.1029/2003GL018201, 2003.
Mursula, and T. Hiltula, Systematically asymmetric heliospheric
magnetic field: Evidence for a quadrupole mode and non-axisymmetry with
polarity flip-flops, Sol. Phys., 224, 133-143, 2004.
Takalo, and K. Mursula, Annual and solar rotation periodicities in IMF
components: Evidence for phase/frequency modulation, Geophys. Res.
Lett., 29(9), p. 31--1-4, doi: 10.1029/2002GL014658, 2002.
T. Hiltula, and K. Mursula, The long dance of the bashful ballerina, Geophys. Res. Lett. , 2006, in print.