Small-Scale Erupting Filaments on the Quiet Sun

Principal Investigator / Institution:  Alan H. McAllister/Helio Research
Co-Investigators:  Sara F. Martin/Helio Research, Karen L. Harvey/Solar Physics Research Corp.
Collaborators: Bruce Lites and Philip Judge/HAO, Jack Zirker/NSO-Sac.Peak

Hermans and Martin (1986) made observations of a new class of tiny filaments, 
averaging 15 arc mins in length.  They appear to have the characteristics 
of larger filaments, but form and erupt rapidly, with an average  
lifetime of about 70 min.  These filaments are also quite 
numerous, with estimates running from 600-1400 per day over the solar
disk.  This means that in a viewing day of 8 hours 2-6 filaments are 
observed in a 5x6 arc min field of view.  It is therefore possible 
to obtain a sizable number of events in a week's observations.
This large number of relatively rapid events will facilitate the
study of basic filament formation and eruption processes.  In particular,
the role of magnetic field evolution can be studied in the relatively 
simple quiet sun. 

It has been realized that these filaments are most likely the 
equivalent (seen on the disk) of those macro-spicules that resemble
erupting filaments (seen at the limb, e.g., LaBonte, 1979).  These
erupting filaments may well play a role in the overall behavior of 
the quiet sun, transporting significant mass and flux into the 
corona.  At the least their eruptions will significantly churn 
the transition region and chromosphere.

While this a new task, contacts have been made with the SOHO team 
and preliminary tests of the observing sequences are already 
underway.  It is expected that such preliminary testing will 
be completed in the fall of 1996.

The GI team will assemble a wide array of groundbased instruments 
that can compliment those aboard SOHO in order to record  
comprehensive data sets that can be used to follow the evolution 
of these small filaments throughout their lifetimes.  The GI 
expects to travel to Goddard to assist with operations during  
the campaigns outlined in the proposal.  The team members have
expertise in the areas for which they are responsible and are well 
qualified to reduce and analyze the data once it has been taken.  
However, they welcome any interested SOHO team members 
to join them in this work.

This proposal seeks to understand a little known class of small 
erupting filaments, which by their shear numbers may be a factor
in the overall physics of the quiet sun.  The proposed combination
of groundbased instruments forms a nice complement to those 
available on SOHO.  We anticipate that together they will be able 
to define the characteristics and dynamics of these filaments, 
and to quantify their contribution to the transport of mass, 
energy, and magnetic flux from the photosphere into the corona.