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AAVSO, 99th Annual Meeting, 2010
Solar Plasma Motion Detection at Radio Frequencies
Very Low Frequencies (VLF)
Solar Ionosphere Detection (SID)
By Rodney Howe MS Remote Sensing, A121
AAVSO, 99th Annual Meeting, 2010Overview of presentation
• How VLF detection works• A computer analysis for SID detection
– Scaling GOES X-ray events to ionosphere disturbance detection with VLF receiver energies
– Evaluate detection possibilities and importance ratings
Howe A121
AAVSO, 99th Annual Meeting, 2010VLF Transmitter locations
AAVSO, 99th Annual Meeting, 2010Transmitting Stations
AAVSO, 99th Annual Meeting, 2010Transmitting Stations
AAVSO, 99th Annual Meeting, 2010Transmitting Stations
AAVSO, 99th Annual Meeting, 2010Transmitting Stations
AAVSO, 99th Annual Meeting, 2010EM Wave Propagation
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AAVSO, 99th Annual Meeting, 2010Inverse Square Law
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AAVSO, 99th Annual Meeting, 2010EM Interaction With Matter
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AAVSO, 99th Annual Meeting, 2010Propagation and Reflection
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AAVSO, 99th Annual Meeting, 2010Reflection vs. Refraction
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AAVSO, 99th Annual Meeting, 2010Ionosphere Structure
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AAVSO, 99th Annual Meeting, 2010e- Density vs. Altitude
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AAVSO, 99th Annual Meeting, 2010Ionosphere Structure
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AAVSO, 99th Annual Meeting, 2010Incoming solar burst..
HAIL project Stanford University
AAVSO, 99th Annual Meeting, 2010
There are two basic VLF receivertypes to validate SID data collection
E field antenna and receiver, whip antenna
H field Gyrator receiver, loop antenna
AAVSO, 99th Annual Meeting, 2010Typical Site Configurations
• Low volume data capture rates– 1 second sample rate– <93,000 samples per Day– Intel (386, 486) Hardware or Equivalent ($<200)– Linux OS ($0) or Windows OS– Analog to Digital Meter ($100), or sound card ($0)– Perl, PHP Programming Languages ($0)– C++ Programming Language ($0)– DSL (0.5 Mbps) ($60/month)– Flat-file, Excel Spreadsheet
AAVSO, 99th Annual Meeting, 2010Example of an E Field Active Antenna
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AAVSO, 99th Annual Meeting, 2010Active Antenna Schematic
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AAVSO, 99th Annual Meeting, 2010Active Antenna Details
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AAVSO, 99th Annual Meeting, 2010Single-channel Receiver
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AAVSO, 99th Annual Meeting, 2010Single-channel Receiver
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AAVSO, 99th Annual Meeting, 2010Logarithmic RF Detector uses the computer’s sound card
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AAVSO, 99th Annual Meeting, 2010Cutler, Jim Creek, & LaMoure
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AAVSO, 99th Annual Meeting, 2010Gyrator VLF receiver
HoweA121
AAVSO, 99th Annual Meeting, 201024 turn 1.5 meter loop H Field Antenna
HoweA121
AAVSO, 99th Annual Meeting, 2010Diode Detector Receiver
A121
AAVSO, 99th Annual Meeting, 2010Both receiver types record alike
A121
AAVSO, 99th Annual Meeting, 2010AAVSO Historical data from Doug Welch
A104
AAVSO, 99th Annual Meeting, 2010Some of the monitoring stations that report to AAVSO are:
• Observer Receiver Location Transmitter and Location• Moos Switzerland FTA - St. Assie, France • Hill Massachusetts, USA NAA - Cutler, ME, USA• Winkler Texas, USA NAA - Cutler, ME, USA• Kielkopf Kentucky, USA NAA - Cutler, ME, USA• Campbell Alberta, CA NLK - Jim Creek, WA, USA• Howe Colorado, USA NML - LaMoure, ND, USA• Mc. Williams Minnesota, USA NML - LaMoure, ND, USA• Samouce Montana, USA NML - LaMoure, ND, USA• Kielkopf Kentucky, USA NPM - Lualualei, HI, USA (2nd receiver)• Mandaville Arizona, USA NPM - Lualualei, HI, USA• Lewis California, USA NPM - Lualualei, HI, USA• Winkler Texas, USA NPM - Lualualei, HI, USA (2nd receiver)
• The observing method employs the monitoring of distant, powerful• VLF radio transmitters; this is a sensitive monitor of the state• of the lower ionosphere along the radio propagation path. Due to• the sub-burst longitude and latitude and the geographical• distribution of LF/VLF beacons and monitoring stations, this burst• was not detected by active monitoring stations in Germany,• Australia and Canada. However, one monitoring station in• Massachusetts, USA (separate from Hill) did not detect the SID• while being in a good location to do so.
AAVSO, 99th Annual Meeting, 2010Solar flare detection requires: SID Start Time, SID Maximum, and the SID End Time (UTC)
A121
AAVSO, 99th Annual Meeting, 2010Importance of Having FriendsTo validate the solar flares
A125
aavso-sid-list@aavso.org <aavso-sid-list@aavso.org>
AAVSO, 99th Annual Meeting, 2010Detection of SID or X-ray transients classified by NOAA-GOES satellites
• Are these VLF receivers sensitive enough to detect A or B class flares detected from the GOES satellites?
• Computer analysis may help answer this question.
A87
AAVSO, 99th Annual Meeting, 2010Mike Hill created software to match GOES satellite event data to SID observers
A87 – A121
AAVSO, 99th Annual Meeting, 2010Matching GOES monthly event data to SID VLF receivers
Solar Flare Summary Based on GOES-8 DataSeptember, 2010
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
B-Class: C-Class: M-Class: X-Class:
A121
AAVSO, 99th Annual Meeting, 2010Matching GOES monthly event data to SID VLF receivers
The importance of collaborating with others to collect and validate data with NOAA’s National Geophysical Data Center (NGDC) .
AAVSO has submitted monthly reports to NGDC since 1980, (for 30 years!), in this format:
ID date start max end IR freq AAVSO-ID
40 040101 0320 0343 0323 1 3WC20 A102
40 040101 0539 0605 0543 1+ 1WC20 A102
40 040101 0653 0707 0655 1- 1WC20 A102
40 040102 0944 1003 0947 1 1WC20 A102
40 040103 1809 1823 1811 1- 5AA24 A87
40 040103 1939 2034 1959 2+ 2XX25 A110
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Sudden_Ionospheric_Disturbances/
AAVSO, 99th Annual Meeting, 2010We can detect B class flares recorded by GOES satellites
AAVSO, 99th Annual Meeting, 2010Evaluating the Importance Rating submitted by SID Observers
A121
0
0.5
1
1.5
2
1- 1 1+ 2 2+ 3 3+
Importance Rating
SID Events Recorded for September, 2010
AAVSO, 99th Annual Meeting, 2010
• The importance rating scale is: • less than or equal to 18 minutes = 1- • 19-25 minutes = 1 • 26-32 minutes = 1+• 33-45 minutes = 2 • 46-85 minutes = 2+ • 86-125 minutes = 3 • greater than or equal to 126 minutes = 3+
Evaluating the Importance Rating submitted by SID Observers
NGDC
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Sudden_Ionospheric_Disturbances/1README.TXT
AAVSO, 99th Annual Meeting, 2010
A Long-Term Project To Set up to:
Match Begin, Maximum and End times to GOES events, so that we can:
Match the NGDC Importance Rating’s to the GOES log scale (A – X) class flares.
Work in progress..
Evaluating the Importance Rating submitted by SID Observers
A121
AAVSO, 99th Annual Meeting, 2010Acknowledgements
• For Helpful Conversations & Encouragement– Joseph DiVerdi, XTR Systems, LLC– Doug Welch, AAVSO-SID, A104– Mike Hill, AAVSO-SID, A87– Susan Oatney, AAVSO-SID, A125– Matt Ettus, GNU-Radio– Peter Wilhelm Otto Arnold Schnoor
• http://www-star.stanford.edu/~vlf/hail/hail.htm
AAVSO, 99th Annual Meeting, 2010
• Questions?
AAVSO, 99th Annual Meeting, 2010NPM @ Lualualei
AAVSO, 99th Annual Meeting, 2010NAU @ Aguada, PR
AAVSO, 99th Annual Meeting, 2010Multi-Channel Observations
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