Stanford VLF Remote SensingScience, Engineering, Educational outreach

Morris CohenAlong with Phil Scherrer, Deborah Scherrer, Umran Inan,

Ray Mitchell, Justin Tan

Space, Telecommunications and Radioscience Laboratory

Stanford UniversityStanford, California 94305

http://www-star.stanford.edu/~vlf/http://sun.stanford.edu

2

Stanford VLF Remote Sensing

� The collaborators

� Ionosphere/magnetosphere overview

� Electromagnetic effects

� SID Receiver

� AWESOME Receiver

� Educational Outreach

3

The Stanford Collaborators

� Phil/Deborah Scherrer

� Ray Mitchell

� Umran Inan

� Morris Cohen

� Justin Tan

� Center for Integrated Space Weather Modeling (CISM)

4

The Ionosphere

Source: HAARP

5

The Magnetosphere

Source: NASA, Rice University

6

Electromagnetic Effects

� 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

7

Sudden Ionospheric Disturbance

� Strong solar flares penetrate to lower ionospheric region, cause transient changes

8

VLF Transmitters

Source: Great Circle Mapper, Karl Swartz

9

SID Event – an Example

2

2.5

3

3.5

4

4.5

5

07:0

0:0

3

07:3

1:2

6

08:0

2:4

8

08:3

4:1

1

09:0

5:3

4

09:3

6:5

6

10:0

8:1

9

10:3

9:4

2

11:1

1:0

5

11:4

2:2

7

12:1

3:5

0

12:4

5:1

3

13:1

6:3

5

13:4

7:5

8

14:1

9:2

1

14:5

0:4

4

15:2

2:0

6

15:5

3:2

9

16:2

4:5

2

16:5

6:1

4

17:2

7:3

7

17:5

9:0

0

18:3

0:2

3

19:0

1:4

5

19:3

3:0

8

20:0

4:3

1

20:3

5:5

3

21:0

7:1

6

21:3

8:3

9

22:1

0:0

1

22:4

1:2

4

23:1

2:4

7

23:4

4:1

0

00:1

5:3

2

00:4

6:5

5

01:1

8:1

8

01:4

9:4

0

02:2

1:0

3

02:5

2:2

6

03:2

3:4

9

03:5

5:1

1

04:2

6:3

4

04:5

7:5

7

05:2

9:1

9

06:0

0:4

2

06:3

2:0

5

Local Nighttime DaytimeSunrise Local Nighttime

0

0.5

1

1.5

2

2.5

3

07:0

0:0

3

07:3

5:3

1

08:1

0:5

9

08:4

6:2

7

09:2

1:5

6

09:5

7:2

4

10:3

2:5

2

11:0

8:2

0

11:4

3:4

8

12:1

9:1

6

12:5

4:4

4

13:3

0:1

2

14:0

5:4

0

14:4

1:0

8

15:1

6:3

6

15:5

2:0

4

16:2

7:3

2

17:0

3:0

0

17:3

8:2

8

18:1

3:5

6

18:4

9:2

4

19:2

4:5

3

20:0

0:2

1

20:3

5:4

9

21:1

1:1

7

21:4

6:4

5

22:2

2:1

3

22:5

7:4

1

23:3

3:0

9

00:0

8:3

7

00:4

4:0

5

01:1

9:3

3

01:5

5:0

1

02:3

0:2

9

03:0

5:5

7

03:4

1:2

5

04:1

6:5

3

04:5

2:2

1

05:2

7:5

0

06:0

3:1

8

06:3

8:4

6

Quiet

Day

Active

Day

NLK

24.8 kHz

Source: Ray Mitchell

10

SID Event – an Example

2

2.5

3

3.5

4

4.5

5

07:0

0:0

3

07:3

1:2

6

08:0

2:4

8

08:3

4:1

1

09:0

5:3

4

09:3

6:5

6

10:0

8:1

9

10:3

9:4

2

11:1

1:0

5

11:4

2:2

7

12:1

3:5

0

12:4

5:1

3

13:1

6:3

5

13:4

7:5

8

14:1

9:2

1

14:5

0:4

4

15:2

2:0

6

15:5

3:2

9

16:2

4:5

2

16:5

6:1

4

17:2

7:3

7

17:5

9:0

0

18:3

0:2

3

19:0

1:4

5

19:3

3:0

8

20:0

4:3

1

20:3

5:5

3

21:0

7:1

6

21:3

8:3

9

22:1

0:0

1

22:4

1:2

4

23:1

2:4

7

23:4

4:1

0

00:1

5:3

2

00:4

6:5

5

01:1

8:1

8

01:4

9:4

0

02:2

1:0

3

02:5

2:2

6

03:2

3:4

9

03:5

5:1

1

04:2

6:3

4

04:5

7:5

7

05:2

9:1

9

06:0

0:4

2

06:3

2:0

5

Local Nighttime DaytimeSunrise Local Nighttime

GOES

Data

Active

Day

NLK

24.8 kHz

11

Cosmic Gamma Rays

12

Chorus Emissions

13

Lightning Detection

EW

NSIncident wave S

Φ

14

Whistlers in the Magnetosphere

15

Whistler Wave – an Example

Sferics

Whistler

Triggered

emissions

Palmer Station, Antarctica 2 March 1992 0839:06 UT

16

Lightning Induced Electron Precipitation (LEP Events)

Source: Bill Peter

17

LEP Events – an Example

Hurricane

Isabel

18

Early Fast Events

Source: Bill Peter

19

Mesospheric Phenomenon

Source: Nikolai Lehtinen

20

Runaway Electrons

Source: Nikolai Lehtinen

21

Sprites and Early/Fast Events

Early fast events are highly correlated with

sprites, indicating connection with ionospheric

heating and runaway electronsSource: Robert Marshall

22

TGFs and Sferics

23

The Hardware

� SID Detector

� AWESOME Receiver

A tmosphericW eatherE ducationalS ystem forO bservation andM odeling ofE ffects

24

The SID Detector

� Designed by Ray Mitchell

� Low cost, compact, easy to use

� Narrowband amplitude receiver

� 1 sample per 5 seconds

25

The SID Detector – Overview

Pre-Amp

24.8KHzFilter

SignalStrength

DATAQComputer

RS-232

Coax

=

All frequencies

DC voltageLevel

10 bit, Analog to DigitalConversion Sample every

5 Seconds

Source: Ray Mitchell

26

SID Detector - Pictures

Pre-Amp DataQPost-Amp

Wire Loop Antenna

Source: Ray Mitchell

27

The AWESOME Receiver

� Designed by Morris Cohen, Justin Tan

� Ultra sensitive

� Medium cost (~$2000)

� Narrowband amplitude/phase

� Broadband 100kHz data

� Deployed worldwide

� Auto-calibration

28

AWESOME Receiver – Overview

B-Field Antenna

PreampLong Cable

Line Receiver

Analog to Digital

ComputerGPS

Antenna

29

AWESOME Receiver – Pictures

30

AWESOME Receiver – Data

Data taken from Palmer Station, Antarctica

31

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

33

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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nQ e it ou s s