Transcript Presentation - Stanford Solar Center

Stanford VLF Remote Sensing
Science, Engineering, Educational outreach
Morris Cohen
Along with Phil Scherrer, Deborah Scherrer, Umran Inan,
Ray Mitchell, Justin Tan
Space, Telecommunications and Radioscience Laboratory
Stanford University
Stanford, California 94305
http://www-star.stanford.edu/~vlf/
http://sun.stanford.edu
Stanford VLF Remote Sensing
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The collaborators
Ionosphere/magnetosphere overview
Electromagnetic effects
SID Receiver
AWESOME Receiver
Educational Outreach
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The Stanford Collaborators
 Phil/Deborah Scherrer
 Ray Mitchell
 Umran Inan
 Morris Cohen
 Justin Tan
 Center for Integrated Space Weather
Modeling (CISM)
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The Ionosphere
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Source: HAARP
The Magnetosphere
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Source: NASA, Rice University
Electromagnetic Effects
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Solar Flare Detection
Cosmic Gamma Rays
Chorus Emissions
Lightning
Whistler waves
LEP Events, hurricane studies
Early/fast Events
Mesospheric lightning discharges
 Sprites, elves, blue jets, TGFs
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Sudden Ionospheric Disturbance
 Strong solar flares penetrate to lower
ionospheric region, cause transient changes
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VLF Transmitters
Source: Great Circle Mapper, Karl Swartz
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Source: Ray Mitchell
06:38:46
06:03:18
05:27:50
04:52:21
04:16:53
03:41:25
03:05:57
02:30:29
01:55:01
01:19:33
00:44:05
00:08:37
23:33:09
22:57:41
22:22:13
21:46:45
21:11:17
20:35:49
20:00:21
19:24:53
18:49:24
18:13:56
17:38:28
17:03:00
16:27:32
15:52:04
15:16:36
14:41:08
14:05:40
13:30:12
12:54:44
12:19:16
11:43:48
11:08:20
10:32:52
09:57:24
09:21:56
08:46:27
08:10:59
Quiet
Day
07:35:31
07:00:03
SID Event – an Example
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2.5
2
1.5
1
0.5
0
NLK
24.8 kHz
Active
Day
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SID Event – an Example
GOES
Data
NLK
24.8 kHz
Active
Day
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Cosmic Gamma Rays
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Chorus Emissions
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Lightning Detection
NS
Incident wave S
Φ
EW
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Whistlers in the Magnetosphere
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Whistler Wave – an Example
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Lightning Induced Electron
Precipitation (LEP Events)
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Source: Bill Peter
LEP Events – an Example
Hurricane
Isabel
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Early Fast Events
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Source: Bill Peter
Mesospheric Phenomenon
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Source: Nikolai Lehtinen
Runaway Electrons
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Source: Nikolai Lehtinen
Sprites and Early/Fast Events
Early fast events are highly correlated with
sprites, indicating connection with ionospheric
heating and runaway electrons
Source: Robert Marshall
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TGFs and Sferics
22
The Hardware
 SID Detector
 AWESOME Receiver
A tmospheric
W eather
E ducational
S ystem for
O bservation and
M odeling of
E ffects
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The SID Detector
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Designed by Ray Mitchell
Low cost, compact, easy to use
Narrowband amplitude receiver
1 sample per 5 seconds
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The SID Detector – Overview
All frequencies
Pre-Amp
Coax
24.8KHz
Filter
Signal
Strength
=
10 bit,
Analog to Digital
Conversion
DATAQ
RS-232
Source: Ray Mitchell
Computer
DC voltage
Level
Sample every
5 Seconds
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SID Detector - Pictures
Pre-Amp
Post-Amp
DataQ
Wire Loop Antenna
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Source: Ray Mitchell
The AWESOME Receiver
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Designed by Morris Cohen, Justin Tan
Ultra sensitive
Medium cost (~$2000)
Narrowband amplitude/phase
Broadband 100kHz data
Deployed worldwide
Auto-calibration
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AWESOME Receiver – Overview
B-Field
Antenna
Preamp
Long
Cable
GPS
Antenna
Computer
Line
Receiver
Analog to
Digital
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AWESOME Receiver – Pictures
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AWESOME Receiver – Data
Data taken from Palmer Station, Antarctica
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More Data, Calibration
Data taken from Homer, Alaska
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Educational Outreach
 Center for Integrated Space
Weather Modeling (CISM)
 Run by Boston University
 Stanford selected for educational outreach
 Distribute SID detectors widely
 3 Beta sites working
 100 units in production
 3 foreign sites planned (Tanzania, India, Tibet)
 Distribute selected AWESOME detectors
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Educational Outreach (con’t)
 Research purpose
 data sent to Stanford via internet, DVDs
 Educational purposes
 Monitor solar flares/VLF activity
 Build antenna, maintain electronics
 Participate in research campaigns
 Promote in developing countries through
UN?
 http://solar-center.stanford.edu/~SID
 http://www-star.stanford.edu/~hail/
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Q u e st i o ns
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