SDO, SID Monitors, and IHY

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SDO, SID Monitors, and IHY

• Dean Pesnell

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What is a Sudden Ionospheric Disturbance?
Ionizing
Dissociating

• One part of the ionospheric response to solar
  flares
• X-rays and UV photons ionize the D-region (60-100
  km), increasing Ne
• During a flare it is the increase in X-rays with
  ? lt 8 Å that cause the effects called SID

The atmosphere absorbs all radiation with ? lt 250
nm, with each wavelength being absorbed at a
different altitude.
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What is a Sudden Ionospheric Disturbance?

• VLF waves (3-30 kHz, ? 10-100 km) are reflected
  by the increased electron density
• If you monitor a remote VLF station you can see
  the enhancements between you and the station

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SID Monitor of Gote Flodqvist in Farste, Sweden
The inset graph shows my results compared with
the satellite GOES-6. During the meridian passage
of the Sun (and summertime) the sensitivity of
the system can be as good as C-level flares. The
transmitter location is Rugby, UK. It transmits
continuously at 60 kHz. One use of SID monitors
is to fill the gaps in the data of the
GOES-system. This satellite is in eclipse from
8-9 UTC.
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Most VLF stations are in the Northern Hemisphere
All information courtesy of Bill Hopkins,
Technical Representative for Pacific-Sierra
Research Corp. Updated by Michael Hill Last
updated 06/20/04
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SIDs, Standford, and SDO

• Solar group at Stanford includes the PI for HMI,
  the helioseismic instrument on SDO
• Same group has proposed to run 15-30 SID
  monitoring stations around the Earth
• Need the equipment for each station
• Have an expert on VLF waves at Sanford

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SIDs and Education

• Simple equipment
• Intel-based Computer (serial-port compatible)
• Receiver
• Antenna
• Communications (Internet or mail)
• Skills Taught
• Construction (build and align antenna)
• Data capture
• Data analysis
• Cooperation with other schools

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SIDs and Education

• SIDs are a day-time phenomenon
• Shows the effects of solar flares
• Other areas of research
• Build receiver for SIDs
• Build receiver for whistlers (nighttime activity)
• Build whistler spectrograph
• VLF and the magnetosphere
• VLF and lightning
• Chemistry during recovery
• Similar research was part of IGY