A Study of the Process of Magnetic Flux Disappearance in Canceling Bipoles

Principal Investigator / Institution: Karen L. Harvey/NOAO
Co-Investigators: Harrison P. Jones, NASA/GSFC, 
Matthew Penn, NSO/NOAO, Donald Hassler, HAO/NCAR

The mutual disappearance ('cancelation') of opposite polarity magnetic flux in 
small bipoles is a common occurrence in surface photospheric magnetic fields 
observations, removing a substantial fraction of the observed magnetic flux 
from the surface.  There is little observational evidence, however, to establish 
if the magnetic flux in canceling bipoles is submerging below the surface or 
continuing to emerge into the solar atmosphere from the photosphere.  This 
proposal is a collaborative research effort to address this problem.

Our study will utilize the comparison of a wide variety of simultaneous data 
from several satellite and ground-based instruments to establish as a function 
of time the height structure of the magnetic fields, velocity flows, and intensities 
associated with small-scale canceling bipoles.  The data base will include magnetic 
and velocity field observations in the photosphere from the SOHO/MDI and at 
two levels in the solar atmosphere with the NSO/KP spectromagnetogaph, 
intensity and velocity information in selected chromospheric, transition region 
and coronal lines from the SOHO SUMER, EIT, and CDS as well as the 
Yohkoh/SXT, high-resolution He I (f10830 filtergrams with HAO CHIP 
instrument, high-resolution H( filtergrams with SOONSPOT and BBSO, and 
high-resolution CaII K filtergrams from NSO/KP.

This proposed investigation relates to NASA's Space Science Program to 
understand the sun by utilizing data obtained by the NASA-funded SOI/MDI 
and the Yohkoh/Soft X-ray Telescope, and NASA's participation in the SOHO 
program.  The strategy for our proposed work is to obtain the necessary 
observations during two observing campaigns and for the PI and Co-Is to 
meet once during the grant period for analysis of the complete data set.  Such 
meetings are an important element of our study to facilitate data comparisons 
and to understand the instrumental and observational constraints and corrections 
of the data.