The Magnetoconvective Occurrence of Spicules &

Their Role in Atmospheric Energetics

orSpicules, Spicules Everywhere.......

Scott W. McIntoshmcintosh@boulder.swri.edu

Southwest Research InstituteDept. of Space Studies

Boulder, CO[Not Possible Without] Support From:

NSF - ATM-0541567NASA SDAC - NNG05GQ70GNASA GI - NNG05GM75G

NASA SR&T - NNG06GC89GHelp Provided [in various forms] By:Bob Leamon - Adnet Services, NASA/GSFC Alisdair Davey & Meredith Wills-Davey -

SwRI/DoSSJoe Gurman - NASA/GSFC

Stuart Jefferies - IfA, UHBernhard Fleck - ESATom Bogdan - NOAA SECPhil Judge - NCAR HAO

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Special Thanks to Dana Loncope

Overview

SOHO/SUMER raster “re-analysis”

Is there a self-consistent explanation?

SOHO/EIT - testing the hypothesis

What does it mean for the SHINE community?

Work based on several papers that are at the (or close to the) submitted stage and a couple of posters that can be found in the sports hall.

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SUMER Re-Analysis 1: Will the real transition region

please stand up?

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Does the fast solar wind

really originate ON the

supergranular network?

Adapted from Hassler et al. Science (1999)

SUMER Re-Analysis A Simple Self-Consistent

Explanation?

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Cartoons Adapted from Wang (1998) & Priest et al. (2002)

SUMER Re-Analysis 1: Will the real transition region

please stand up?

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Does the fast solar wind really originate ON the supergranular

network?

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Coronal HoleQuiet SunChromospher

e

10,000K

Transition

Region

100,000

K

Transition

Region

600,000

K

SUMER C IV

Intensity/Doppler Comparison

Quiet Sun: Network very red-shiftedVery few blue-shift locations, most adjacent to cell vertices (4% of pixels).Coronal Hole:LOTS more blue-shifted regions (22% of pixels). Very few on boundaries although most are close. Mean distance 7Mm.Considerable drop (40%) in cell interior emission.

SUMER Re-Analysis: The Global Scale

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- Ne VIII blue-shift in the CH not isolated only to network vertices, 65% lies to the cell-interior side of the boundary. NO obvious correlation of the blue-shift pattern to that of the gross chromospheric network.- Cell interior emission of C IV and Ne VIII is ~40% less than in the QS.

- The vast majority of strong Ne VIII outflows lie in locations of locally unbalanced magnetic fields.

- Large portion of the CH cell interiors (25%) contains C IV blue-shifts and they are closer to cell boundaries than cell centers - only 10% lie within 2Mm of a boundary. QS contains very few CIV blue-shifts (5%), but they neighbor network vertices.

- 92% of the C IV blue-shifts in the CH lie “under” Ne VIII blue-shifts.

- Magnitude of the blue-shift (CIV & NeVIII) is tied to the amount of unbalanced magnetic field present.

The key to understanding these relationships lies in understanding the C IV pattern and how it ties to Si II and Ne VIII

SUMER Re-Analysis A Simple Self-Consistent

Explanation?

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Cartoons Adapted from Wang (1998) & Priest et al. (2002)

EIT 304Å - Testing The Hypothesis

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Small-scale brightenings occur all over the region - is there a familiar pattern?

The SUMER results have provoked a

simple analysis of long-duration (rare) SOHO/EIT 304Å data to test this hypothesis.

“CME Watch” (12m)“Submode 6” (6m)and “Shutterless” (76s)sequences

Details of the analysis and discussion can be found on the poster.

He II - 25,000K(upper chromosphere

lower transition region)

EIT 304Å - Testing The Hypothesis

De-rotate, co-align and stack the EIT 304Å image

sequence.

Analyze the pixel timeseries:

- form intensity distribution

- fit to distribution- compute moments of

distribution- remove the trend

variation-compute δI/I

- identify “events” - changes in δI/I

Combination of these components allow us to study the spatial and

temporal variation of the He II emission in

relation to the coronal plasma and photospheric magnetic environments

EIT 304Å - Testing The Hypothesis

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“EUV Blinkers” - ESA/NASA MDI & CDSTarbell et al. (1998)

The relentless emergence, advection and eventual destruction of magnetic flux on supergranular scales is responsible for the mass loading, heating and initial acceleration of plasma at the base of the solar corona and wind.

The local field conditions control the rate and scale of the energy release.

The global magnetic field topology controls how the energy is released and utilized by the plasma.

The same simple model can explain and be explicitly tied many solar phenomena - named differently because they are observed in different wavelengths.

What Does this Mean for the SHINE Community?

A Case Study - Coronal Dimming & Transient Coronal Holes

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From “The Post-Eruptive Evolution of a Coronal Dimming” McIntosh, Leamon, Davey &

Wills-Davey 2006 Submitted, ApJL

Let me know if you would like to see all of the movies/data

Dimmings & CMEs tiedObserved in EIT 195Å July 6, 2006

Contours are 40% reduction in intensity from t=0

Observed with TRACE too Watch the “moss”

Compare to the Flux Balance of the Region and it’s evolutionWe can use the results

provided above to study the relationsip between the asymmetry, apparent motion, shape and eventual stalling of the dimming region with the magnetic environment.

Solar wind initiation and atmospheric plasma heating CAN be performed with ONE single process. “Spicules” are the basic building block of that process.

The smaller scale magnetic unbalance (-20Mm) controls the ferocity of the reconnection and the resulting energy release.

The global magnetic topology of the plasma acts as the “thermostat” - controlling the energy balance between kinetic and thermal dominance.

Coronal dimmings [transient coronal holes], CMEs and POSSIBLE secondary acceleration from following fast spicular wind streams..........TBD

The Laundry ListWorking on the “if it walks like a duck...” principal we have seen that the spectroscopic, imaging and wave signatures observed are all consistent with the ubiquitous driving of the solar plasma by magnetoconvection-driven reconnection.

We present a suite of observations from ground and space based observatories that highlight the role of megnetoconvection in delivering energy and mass into the quiet solar atmosphere and the solar wind. The energy (and mass) is supplied by magnetic reconnection ejecta that are intimately tied to the scale of supergranulation; spicules. The relentless nature of magnetoconvection makes it an ideal "basal" energy release mechanism for the Sun and other stars. The results of the analysis presented pose interesting questions for the theorists and modelers of the SHINE community.

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Abstract

SUMER Si II

Intensity/Doppler Comparison

Supergranule cell boundaries from advanced “watershed” segmentation.

Mean measured cell diameter ~30Mm.

Possible signature of convective “overturn” on cells.

SUMER Ne VIII

Intensity/Doppler Comparison

Quiet Sun: Bulk blue-shift located at network “vertices.No apparent correlation of blue-shift with rest of network cell pattern.Coronal Hole:LOTS more blue-shifted regions.Considerable drop (40%) in emission.Still no apparent correlation of blue-shift with network cell pattern, but appear mostly on interior-side of cell boundaries.

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Testing TheoryClassically, the acoustic cut-off, ωac, is the frequency below which waves in a gravitationally stratified atmosphere (with no magnetic field) should be evanescent? For solar parameters ωac~5.4mHz.Theoretically, Bel & Leroy [A&A, 55 239 (1977)] predicted that where there is a magnetic field, running waves are permitted below ωac in certain magnetic conditions. ωac is modified by the “effective gravity on the field line”, the cosine of the field angle to the vertical. The larger the field angle (above 30 degrees) the lower ωac goes.

This can be checked observationally.......Easiest place, most organized field, is in a sunspot........

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“Rings” of running waves, move outward as field angle increases

Decreasing FrequencyFull Movies

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Not only, but also....

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MOTH “movie” @ 4mHz

Prompts the age-old nugget: “If it looks like a duck, walks like a duck, quacks like a duck, then it probably is.....” [James Whitcomb Riley, circa 1883]

Watch the quiet Sun. The variation observed is NOT noise.

What is the dominant spatial scale?

There is a very slowly evolving pattern with an apparent “twinkling” superimposed.

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3mHz (5-minute) waves oozing out on super-granular boundaries.

A Situation just like before. Now the convection-driven reconnection near the super-granule boundary creates a magnetic field topology that permits the p-modes from the solar interior to escape into the upper atmosphere.

Interpreting the Sub-ωac Running Wave PatternWee magnetic flux concentrations ducting p-modes into the chromosphereas low-beta slow modes. One man’s p-mode absorption is another man’s bounty......[Doug’s Talk]

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Going one Step Further....

ν<5.4mHz : E.F. ≿1.6kWm-2

-Escaping p-modes potentially carry a lot of energy from the solar interior outward.

-MOTH measures Doppler velocity at two heights.

We can estimate the observed amount of energy carried by these low-frequency running waves at, say the midpoint between K and Na.

E.F.(ν) = PV(ν) ρ(z=500) PTT(ν) [cs

2/δz]

Note: It takes an integrated energy flux of ~4.3kWm-2 to overcome the radiative losses of the chromosphere at the height of Potassium....[Vernazza et al. 1981, ApJS,

48, 635]

It could be that, at least 40% of the energy required to overcome chromospheric radiative losses is ready supplied by p-mode leakage facilitated by the action of the magnetic carpet.