Update to the Babcock-Leighton Solar Dynamo and Activity ...

Update to the Babcock-Leighton Solar Dynamo and Activity Predictions

Kenneth SchattenAi-solutions

Outline• UPDATE BABCOCK-LEIGHTON DYNAMO

1) Shallow Dynamo

2) Percolation controls small-scale motion

3) Magnetic forces control large-scale motion

• PERCOLATION COMES IN TWO FLAVORS:1) Highly Superadiabatic: Convection drives like-sign Ephemeral Regions (EPRs ) into sunspots

2) Normal: Normal T structure: field concentrations disperse: spots-> faculae / plage

• MODELING:

Cellular Automata Modeling – relate to observations & solar dynamo

• PREDICTION:

Solar Cycle #24 Rz~75; F10 ~125 in ~2012-3

Babcock-Leighton Solar Dynamo

Magnetic Carpet & Percolation

From Lockheed Group

Above the PhotosphereBelow the Photosphere:In regions of high superadiabaticity, like fields drawn together

Percolation Allows Field to Separate from the Flow – Remain Shallow

Falling Leaf Instability

Superadiabatic Temperature Gradient: Large in Top Layers

Overview – Shallow Dynamo:A) and B) – Superadiabatic Percolation

C) Normal Percolation

Overview – Shallow DynamoLike Babcock-Leighton, but with 1) EPRs and 2) motio n from B forces

Superadiabatic Percolation Model

Percolation

Time Series of Superadiabatic

Percolation of Ephemeral Regions

1

2

3

4

5

6

Super + Drift Normal + DriftSuperadiabatic

Modeling and Observations

Modeling and Observations

400 & 100 Year ModelingPolar Fields vs. Time

-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

0 50 100 150 200 250 300 350 400

Time, Years

Pola

rFi

elds

,ar

bitr

ary

unit

s

North Polar Field Data South Polar Field Data

Different Longitudes, Both Polar Fields

-1500

-1000

-500

0

500

1000

1500

2000

100 110 120 130 140 150 160 170 180 190 200

Time, years

Magnetic

Field,

arbitrary

units

Series1 Series2 Series3 Series4

Series5 Series6 Series7 Series8

How Spot Flux Imbalances Form(Why spots are not all equal bipoles)

SODA index vs time, years

0

50

100

150

200

250

1975 1980 1985 1990 1995 2000 2005 2010

Time, years

SO

DA

Inde

x

Toroidal proxy (radio flux) Polar Field (soda units) SODA index

SODA (Solar Dynamo Amplitude) Index

Schatten Prediction: Weak Solar Cycle 24Use of the idea that the Sun’s polar field is a precursor for the

next cycle’s activity level [Schatten et al. (1978)]; Svalgaard et al. (GRL, 32, L01104, 2005); Schatten (GRL,32,L21106, 2005)

F10.7 Observations and Predicts

0

50

100

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250

300

1970 1980 1990 2000 2010 2020Year

Rad

io F

lux, F

10.7

Observations Predicted in Advance

Geomagnetic Activity - Sunspot Correlation

Activity Index (aa)

Max

imum

Sun

spot

# (

Rz)

Conclusions• UPDATE BABCOCK-LEIGHTON DYNAMO:

We update with 3 ideas: 1) Shallow Dynamo, 2) Percolation in two flavors, a nd 3) Magnetic forces help drive faculae/plage towards poles

• PERCOLATION IN TWO FLAVORS: 1) Highly Superadiabatic: Convection drives like-sign Ephemeral Regions (EPRs ) into sunspots2) Normal: Normal T structure: field concentrations disperse: spots-> faculae

• MAGNETIC FORCES: Rather than fields moving towards poles via diffusion/meridional transport, we suggest magnetic forces, mB, on subsurface field elements play a prominent role– yie ld dynamo

• MODELING: Cellular Automata Modeling seems to fit s olar dynamo

• PREDICTION: Solar Cycle #24 Rz~75; F10 ~125 in ~201 2-3

Backup

LONG-TERM SOLAR OBSERVATIONSInternational/Zurich Sunspot Number vs. Year

0

20

40

60

80

100

120

140

160

180

200

1700 1750 1800 1850 1900 1950 2000Time, Years

Inte

rnat

iona

lSun

spot

Num

ber

51 64 1032 71 8 91 11 12 13 14 15 16 1718 19 2021 235 22

SODA index vs time, years

0

50

100

150

200

250

1975 1980 1985 1990 1995 2000 2005 2010

Time, years

SO

DA

Inde

x

Toroidal proxy (radio flux) Polar Field (soda units) SODA index

Babcock’s shallow dynamo view

Babcock 1961, ApJ, 133, 572

Why Field Separates From Flow: Leaf Instability, and Stays Near Photosphere