DIAGNOSTICS OF SUBSURFACE MAGNETIC FIELDS,
MASS FLOWS AND THEIR SPATIAL GRADIENTS FROM TIME-DISTANCE ANALYSIS
M. Ryutova
In collaboration with the time-distance analysis team (Stanford) and
the correlation tracking team (Lockheed)
A new method of obtaining the information on the subsurface
plasma flows and magnetic fields using the the sine and cosine
convolutions of measured propagation times will be extended for the
reconstruction of the spatial inhomogeneities of subsurface magnetic fields
and plasma flows. As it was shown the convolutions with respect to first
harmonics contain an information on the direction and absolute value of
the flow velocity, while second harmonics describe predominantly the
orientation and absolute value of horizontal magnetic fields and the
spatial gradients of plasma flow. Specifically, the sum of forward and
backward propagation times (their second harmonics convolutions) allows
to find the distribution of magnetic field. The second harmonic convolutions
of the time difference gives the spatial distribution of the divergency
of flow. The third harmonics are related to magnetic field inhomogeneities.
We propose to use this technique to reconstruct the distribution of the
magnetic fields and flows including the flow divergency at different
depth corresponding to time-distance measurement taken for different
annuli.
We will use this technique to reconstruct the distribution of the
magnetic fields and flows including the maps of the divergence of
flow. The reconstructed maps obtained for the different subsurface layers
will be analyzed together with the surface maps obtained for the same day
by the correlation tracking method developed by Lockheed group.
The reconstructed maps will be compared and analyzed
with the magnetograms of subsequent days: the reconstructed maps
show the concentration of magnetic field in some subsurface regions
which have no counterparts on the visible surface, and which may be a source
of the flux yet to be emerged.