Transcript Athabasca University Initiatives supporting THEMIS M. Connors, K. Hayashi, C. T. Russell, K.

Athabasca University
Initiatives supporting THEMIS
M. Connors, K. Hayashi, C. T. Russell,
K. Shiokawa, R. Irwin, G. Rostoker
(AU, U. Tokyo, UCLA, STELAB,
Northern Lakes College, U. of Alberta)
THEMIS Launch Meeting, Cape Canaveral, Florida – Feb 2007
Image: Mikko Syrjäsuo
Three Main Thrusts
1. AUGO (Athabasca University Geophysical
Observatory) is a comprehensive facility in
the equatorward part of the auroral zone
2. Magnetometer networks including
AUTUMN, help for STEP, and AU/small.
Associated inversion techniques (AFM).
3. Participation in e-POP (ground and outreach)
1. Athabasca University Geophysical
Observatory (AUGO)
54.72 N, 246.7 E
CGM (2005)
62.0, 306.5
L=4.55
Founded 2002
(UCLA mag 1998)
AUGO’s STELAB Instrumentation
As described by Sakaguchi and Shiokawa here:
1. multispectral ASC including Hβ
2. 64 Hz induction coil
3. proton spectrometer
2. Ground Magnetometry
In a Sun-to-Mud approach, we are in the mud…
EDMO UCLA magnetometer installed by Martin Connors (Tom Sawyerlike technique applied to astronomer Brian Martin) in December 2004
Often the locales are less agreeable than Florida (Kanji Hayashi
in LaRonge, Canada, mid-October 2004)
Paddle Prairie
Athabasca
Edmonton
Red Deer
Calgary
Lethbridge
Sites
installed
fully and
data
available (2
Hz) since
Oct 4, 2005
Inuvik 2006
Athabasca University
has assisted or runs 16
sites in Canada (white
triangles and purple
dots in Western
Canada). Most data
available through
UCLA, STEP website,
or on request. PEA,
KAQ, SFV hoped for
soon. New Polaris sites
on E. Coast of Hudson
Bay to be installed in
2007.
Some GBOs not shown.
What can ground magnetic data tell us?
Regrettably, a single
magnetogram often
tells nearly nothing
and even multipoint
measurements from a
meridian chain are
difficult to interpret,
needing…
“geomagic”…
Automated Forward Modelling (AFM) can help.
For meridian data, AFM adjusts current and
borders
The method is however, much more general and
includes field-aligned currents in realistic 3-d
configurations. Midlatitude perturbations can be
included as can a Dst-like parameter.
Inversion tells us more by giving simple parameters
extracted from several ground stations
April 10 1997
Array Interpretation from a distributed region is even
more difficult, complicated by problems of
nonuniqueness. An inversion procedure is needed.
• On the ground, one
detects primarily the
magnetic effects of the
Hall currents associated
with the auroral oval
electric field
• FAC effects are not dealt
with in this talk but CAN
be observed from the
ground
AFM Apr 3 1997 red vectors are
model, black observed
Ability to match input data is best near the middle of the chain
(although often not in Z due to electrojet structure)
Note: different event and stations
Independent confirmation: Comparison of optical borders from
meridian scanning photometer and inversion results for growth
phase (Feb 22 1997); also confirmed by FAST FAC detections
FAST
Two electrojet model
results are shown
superposed on 557.7
nm optical meridian
scan data from
Gillam. The growth
phase arc is poleward
of the evening sector
eastward electrojet.
Note that the method
is sensitive to initial
conditions
Talking about satellites, e-POP should launch in 2008,
perfect timing to complement THEMIS
e-POP will have a
comprehensive
and in many ways
innovative
instrument
package (see Yau
et al., Adv. Space
Research, 2006)
Conclusions
• Efforts at Athabasca University will come to
fruition in the THEMIS/e-POP era:
AUGO – Magnetometer Networks – e-POP
• Our own data is distributed freely: that of guest
instruments often also is
• Some issues of data archiving/distribution
exist
• Budget is low for needed increases in ground
coverage
Acknowledgements
• D. Boteler (NRCan), Mark Moldwin (UCLA), Eric
Donovan and Brian Jackel (U. of Calgary), Brian
Martin (King’s University College), Stu Harris (UC
Berkeley ) for help in placement and operation
• Canadian Space Agency and University of Alberta for
CANOPUS/CARISMA data
• This work funded by Canada Research Chairs,
Canada Foundation for Innovation, AU, and NSERC