Frank Hill
NSO/T Scientific Staff
Areas of Interest
Helioseismology, Asteroseismology, Fluid Dynamics of the Solar Convection
Zone, the Solar Activity Cycle, Digital Libraries
Recent Research Results
Hill continues to perform research in helioseismology. Currently he is
focusing his efforts on
improving the estimates of the parameters that describe the features (peaks,
ridges, rings) in the
solar acoustic spectrum. These parameters are the fundamental data for
helioseismology and
provide the foundation on which rest all inferences about the solar interior.
Consequently, Hill
is working on advanced time-series analysis including multi-tapers and
wavelet denoising with
P. Stark (UC Berkeley), R. Komm, Y. Gu, and S. Jefferies; and with R. Howe on
detailed
calculations of the spatial leak structure arising from the
non-orthonormality of spherical
harmonics on a partial sphere. Hill is also working with R. Howe and R. Komm
on solar cycle
variations of the oscillation parameters. Recently they found a very tight
correlation between
the even frequency splitting coefficients and the corresponding components of
the latitudinal
surface distribution of the magnetic field. In addition, there is now
preliminary observational
evidence that the amplitudes and life times of the modes also evolve with the
activity level. This
work will continue as cycle 23 progresses. Finally, Hill is an active member
of the Stellar
OScillation Network Group (SONG), which has been awarded 30 orbits of Hubble
time in the July 1999 quarter.
Service
Hill serves as the GONG Data Scientist, developing algorithms for the
reduction and analysis of
data for global helioseismology. He serves as the NSO Digital Library
Scientist, using an NSF
Space Weather Program grant to place NSO data on-line and accessible over the Internet. This
service is now available at the URL http://www.nso.noao.edu/diglib. Hill is
also working on
plans for the SOLIS data archive. Hill typically supervises six staff
members, currently three
scientists, one programmer, and two data technicians. Hill is a member of the
NOAO Stellar
Oscillation Network Group (SONG) Steering Committee, the IAU Commission 12
Organizing
Committee, the IRIS helioseismology network Scientific Committee, and the
NASA Space
Physics Data System Solar Physics Discipline Team. Hill is a member of the
NSO Telescope
Allocation Committee. He participated in the Passport To Knowledge Live From
The Sun program.
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Updated: 28Jun1999