We analyze both Kitt Peak magnetogram data and MDI continuum intensity
sunspot data to search for the following solar toroidal band properties: width
in latitude and the existence of a tipping instability (longitudinal m=1 mode)
for any time during the solar cycle. To determine the extent which we can
recover the toroidal field dynamics, we forward model artificially generated
sunspot distributions from subsurface toroidal fields we assigned certain
properties. We analyzed two sunspot distribution parameters using MDI and model
data: the average latitudinal separation of sunspot pairs as a function of
longitudinal separation, and the number of sunspot pairs creating a given angle
with respect to the E-W direction. A toroidal band of 10 degrees width with a
constant tipping of 5 degrees best fits MDI data early in the solar cycle. A
toroidal band of 20 degrees width with a tipping amplitude decreasing in time
from 5 to 0 degrees best fits MDI data late in the solar cycle. Model data
generated by untipped toroidal bands cannot fit MDI high latitude data and can
fit only one parameter at low latitudes. Tipped toroidal bands satisfy chi
squared criteria at both high and low latitudes. We conclude this is evidence
to reject the null hypothesis - that toroidal bands in the solar tachocline do
not experience a tipping instability - in favor of the hypothesis that the
toroidal band experiences an m=1 tipping instability. Our finding that the band
widens from ~10 degrees early in the solar cycle to ~20 degrees late in the
solar cycle may be explained in theory by magnetic drag spreading the toroidal
band due to altered flow along the tipped field lines.Comment: This paper is accepted to Astrophysical Journal, September 2005 issu