Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Solar and Heliospheric Report

J. RyanTrevor Morgan

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Diversion of effort for last 6 months

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Recent Activity35% GLE increase in Oulu

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Were working on 2005 January 20 GLE. Most intense event in 50 years.

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Progress on 2005 January 20

• Started simulations to re-evaluate throw area for scalers (for proper effect. area)

• Started simulations to determine effective area for various scalers

• Started simulations using pencil beam from zenith to study multiplicity dependence on incident directions (to confirm or reject overhead beam).

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Interest in (1) extended emission or (2) isotropized population, either of which could produce tail.What is J at Milagro/Climax as compared to elsewhere?

What is A in spike and how does it evolve?What is happening at 0800? instruments see extended emission. Do we?Milagro sees second increase at 0700, but not Climax??

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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8.5

8.0

7.5

7.0

6.5

6.0

x106

03:00 06:00 09:00 12:00 15:00

UT

High Threshold Rate2005 January 20

Need to flatten baseline

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Science Qs

• Interplanetary conditions?– Solar wind speed (guiding center path)

– Turbulence level (rise time) (appears to be low)

• CME lift-off time and speed. (Release time)

• Hard X-ray onset time.• Signals from other NMs to ‘estimate’ anisotropy. (1/cos )

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Halloween Event

3800

3600

3400

3200

3000

2800

10/18/03 10/23/03 10/28/03 11/2/03

UT

1.35

1.30

1.25

1.20 2003 October/November

Climax Milagro

1.5%

6%

3.2%/day

4.3%/day

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Science Questions

• Spectrum of Decrease• Anisotropy of Decrease

– Depends on magnetic fields 1. In front of shock2. Behind shock3. Inside ejecta4. Behind ejecta

– Should see A change in time.

• Recovery time vs. energy (backfilling heliosphere)

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Tasks• Continue sims for area and multiplicity.

• Need a muon fitter to study triggered events in Forbush decreases.

• Restart work on PCA description of background to compare to UCSC work. Applies to both scalers and triggered events.

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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More work

• Need environmental correction factors for long periods, i.e., days.– Which way does stratospheric temperature effect go and how large is it?

– Should first simulate effect for T at loft.

• Instantaneous cutoff ridigities for Climax/Fenton Hill/MW/Durham

Dec. 18-19, 2006 MilagroCollaboration Mtg.

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Other investigations

• How many GLEs have we really registered? Need a systematic look, triggered off, probably, Climax curves.

• How many Forbush decreases have we registered? (Triggered and scalers) Can also do a selective search here using MW or Durham data.

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Upcoming Events

• Spring General Assembly AGU– Acapulco

• ICRC Yucatan• AOGS Bangkok• AAS Honolulu