| Sunday, December 7 | ||
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| 16:00-19:30 | Registration Desk Opens | |
| 19:30-22:00? | Welcome Reception with Chocolate Fountain | |
| Monday, December 8 | ||
| 08:00 | Registration Desk Opens | |
| I | Chair: Emslie | |
| 08:30 - 09:00 | Welcome, Overview | |
| 09:00 - 09:50 | Opening Keynote: D. Hathaway: Solar Activity Cycles - Past and Future |
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| 09:50 - 10:10 | L. Svalgaard: Recalibration of the Sunspot number and Consequences for Predictions of Future Activity and Reconstructions of Past Solar Behavior |
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| Leif Svalgaard & Ed W. Cliver: Already Rudolf Wolf [1859] knew that there is a very tight, linear relation between the Sunspot Number [SSN] and the amplitude of the daily variation of the geomagnetic elements. In fact, he used that relation to calibrate his sunspot series when using data from other observers not overlapping in time with his own. There is a very good physical reason for this relationship since the solar FUV, that depends on the SSN, determines the conductance of the ionosphere and hence the strength of the currents and their magnetic fields generated by dynamo mechanisms. When Wolf died in 1893 his successors did not appreciate the elegance of Wolf's calibration method and the SSN calibration suffered several discontinuities. We show from our modern understanding of the ionosphere and its current systems that Wolf's method is physically sound and can be used to detect and correct errors in calibration. The re-calibrated SSN shows that the Sun in the 20th and 21st centuries has not been particularly more active compared to activity in the 19th century. Since the SSN is often used as input to various schemes [both statistical and physics based] for prediction of solar cycles and reconstructions of TSI, such re-assessment has important implications for a wide swath of applications. | ||
| 10:10 - 10:30 | L. Fletcher Evolving views of solar flares, and targets for Cycle 24 |
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| Until the middle of the 20th century, flares were known as 'chromospheric flares' or 'chromospheric eruptions', indicating that the role of coronal magnetism in the flare phenomenon was not appreciated. The flourishing of solar coronal physics that followed the opening-up to observation of the UV to X-ray spectrum led to rapid developments in theories of coronal energy storage and of the catastrophic release that is a flare. The overall 'cartoon' framework of a solar flare is reasonably well-established (though there are still significant theoretical challenges) and many aspects are supported observationally. However, this cartoon does tend to be particularly sketchy in its view of the chromosphere, which is where the most important flare diagnostics originate. In this short overview I will discuss some key aspects of how ideas about solar flares have developed over recent cycles and suggest that in the coming cycle we need to turn our attention back to the chromosphere. | ||
| 10:30 - 11:00 | BREAK | |
| II | Thematic Session 1, Chair: Fleck | |
| 11:00 - 11:50 | A. Van Ballegooijen: Global Magnetic Field Evolution | |
| 11:50 - 12:10 | T. Hoeksema: Relationship between the High and Mid latitude Solar Magnetic Field. |
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| The discussion about the relationship between the high- and mid- latitude magnetic field and, in particular, the solar activity has deep roots since Horace and Harold Babcocks measured the solar magnetic field on the Sun (1955) and Sheeley has published a time series of the polar faculae (Sheeley, 1964, 1966). From one side, it led Babcock (1961) to the understanding of the polar magnetic field as a result of the transport magnetic field from activity belts in the mid-latitude to the poles due to the meridional circulation. These "streams" correspond to the unipolar magnetic regions (Bumba, Howard, 1965) stretched eastward and poleward by differential rotation, and drift toward the pole. For describing the transport of the magnetic energy from the mid-latitude to the high-latitude Leighton (1964, 1969) applied a random-walk process associated with the convective supergranulation. All these investigations has become a base for the modern solar cycle transport models, in which the polar magnetic field is a result of acting the turbulent diffusion, differential rotation and meridional circulation. > From the other side, the development of the polar faculae and statistics of the ephemeric regions (Harvey, 1991) led the idea about 'Extended' solar cycle. Recent investigations in the heliosesmology (Howe et al., 2006; Antia, 2008) point out on the presence of the zonal flows which are related to the zonal or axisymmetrical distributions of the large-scale magnetic field and coronal activity (Antia, 2001). Nowday, we have long-term time series of solar magnetic field from Mount Wilson (MWO), Wilcox (WSO) and Kitt Peak Observatories (NSO/KPO). The weak polar magnetic field in cycle 23 leds to the prediction of small solar cycle 24 (Svalgaard, 2004). But question is still open how the polar magnetic field of the current cycle relates to the initial poloidal magnetic field which produces the toroidal field of the next solar cycle according to the dynamo theory. In my presentation I discuss all abobe mentioned problems and represent the results of the investigations of the SOHO/MDI data concerning the relationship between the high and mid latitude activity. | ||
| 12:10 - 12:30 | H. Peter: Magnetic connectivity and coronal dynamics | |
| Using numerical experiments one can gain considerable insight into the processes governing the evolution and dynamics of the corona, even though one has to apply simplifying assumptions. In the framework of a 3D MHD model one can describe the formation of a corona with its loops systems forming including the complex magnetic interaction of different structures. This shows that our concept of a 1D loop is mostly applicable in active regions, but might be questionable if considering structures above the quiet Sun network (or in more active stellar coronae). While these models give results providing answers to a number of long-standing problems, we have to re-visit some of the basic simplifications, most notably concerning the dissipation and transport of energy. Only if we understand how to include these processes properly into (macroscopic) simulations, we might hope to understand the corona and its change from solar minimum to maximum. | ||
| 12:30 - 14:30 | LUNCH | |
| III | Thematic Session 2, Chair: Hannah | |
| 14:30 - 15:20 | A. Vourlidas: The Flare-CME Connection: What Answers Could the Next Solar Cycle Provide? |
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| The past solar cycle 23 has been the best observed solar cycle ever. Thanks to the successful operation of SOHO, it has been the first full cycle observation of the corona by space-based remote sensing instruments. We now have a wealth of EUVI, white light and X-ray observations of Sun's most energetic events; namely, flares and coronal mass ejections (CMEs). Their analyses have been at the focus of solar physics research for decades. We entered cycle 23 with a strong controversy over the importance and the relationship between these two forms of energy release. But we will enter the next cycle with a much cleaner view of the flare-CME connection. In this talk, I will review our current understanding of the interplay between flares and CMEs, ask us to rethink the standard definitions for these two terms and emphasize the areas where progress is still to be made in cycle 24. | ||
| 15:20 - 15:40 | R. Moore: The Flare/CME Connection |
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Ron Moore, David Falconer, Alphonse Sterling
NASA/MSFC/National Space Science and Technology Center
We present evidence supporting the view that, while many flares are produced by a confined magnetic explosion that does not produce a CME, every CME is produced by an ejective magnetic explosion that also produces a flare. The evidence is that the observed heliocentric angular width of the full-blown CME plasmoid in the outer corona (at 3 to 20 solar radii) is about that predicted by the "standard" model for CME production, from the amount of magnetic flux covered by the co-produced flare arcade. In the standard model, sheared and twisted sigmoidal field in the core of an initially closed magnetic arcade erupts. As it erupts, tether-cutting reconnection, starting between the legs of the erupting sigmoid and continuing between the merging stretched legs of the enveloping arcade, simultaneously produces a growing flare arcade and unleashes the erupting sigmoid and arcade to become the low-beta plasmoid (magnetic bubble) that becomes the CME. The flare arcade is the downward product of the reconnection and the CME plasmoid is the upward product. The unleashed, expanding CME plasmoid is propelled into the outer corona and solar wind by its own magnetic field pushing on the surrounding field in the inner and outer corona. This tether-cutting scenario predicts that the amount of magnetic flux in the full-blown CME plasmoid nearly equals that covered by the full-grown flare arcade. This equality predicts (1) the field strength in the flare region from the ratio of the angular width of the CME in the outer corona to angular width of the full-grown flare arcade, and (2) an upper bound on the angular width of the CME in the outer corona from the total magnetic flux in the active region from which the CME explodes. We show that these predictions are fulfilled by observed CMEs. This agreement validates the standard model. The model explains (1) why most CMEs have much greater angular widths than their co-produced flares, and (2) why the radial path of a CME in the outer corona can be laterally far offset from the co-produced flare. This work was supported by NASA's Science Mission Directorate through its Heliophysics Guest Investigators Program, Its Living With a Star Targeted Research & Technology Program, and its Solar and Heliospheric Physics Supporting Research & Technology Program; and by NSF through its SHINE Program. | ||
| 15:40 - 16:00 | L. Culhane: Hinode and the Flare/CME Connection: The Events of 19th May 2007 |
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| A GOES class B9.5 long duration flare was observed on 19 May, 2007 by Hinode and other space and ground-based systems. It was part of a complex set of events that included filament eruption, two CMEs, dimming and a propagating global wave. In the days prior to the flare and eruption, two filaments - one active and one quiescent, appeared on May 17/18. Following repeated interaction and heating episodes in the 27 hour interval before the flare, both partcipated in the eruption. We will briefly discuss these observations and examine the nature of the flare in the context of the eruption. In particular Hinode EIS spectra suggest the presence of early heating and turbulence due to flare-associated shocks. | ||
| 16:00 - 16:30 | BREAK | |
| IV | Thematic Session 3, Chair: Doschek | |
| 16:30 - 17:20 | H. Isobe: Active-region Dynamics, Flux Emergence, and Bright Points |
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There are variety of transient enegy release events in active regions:
microflares, X-ray/EUV jets, transition region explosive events,
chromospheric jets and surges, Ellerman bombs etc.
Significance of studying these events has two aspects.
Firstly, they are the prototypes of more complicated flares and
other magnetic enegy release events in astrophysics.
Many ``cartoon models'' have been proposed on the basis of
observations and numerical simulations, and most of models invoke
magnetic reconnection driven by flux emergence, flux cancellation
and shear motions. I will review some of recent progresses in this regard.
The second aspect is that these different types of events provide a unique laboratory for basic plasma physics. For example, fast magnetic reconnection is believed to occur at various heights in the solar atmosphere, but the plasma parameters changes enormously from weakly ionized, fully collisional photosphere to fully ionized, almost collisionless corona. What is believed to play a role in coronal reconnection, such as microscopic instailities and wave-particle interactions, are unlilely to occur in fully collisional photosphere/chromosphere. Instead, Hall and ambipolar effects may play a role in fast reconnection in these layers. But theoretical studies on reconnection in these layers are few, and observational studies are even fewer. Solar physics in cycle 24 should extend into this direction, in short, beyond cartoon models. | ||
| 17:20 - 17:40 | G. Fisher: Estimating Electric Fields from Vector Magnetogram Sequences |
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| The advent of extensive ground-based and space-based vector magnetogram data will greatly improve our quantitative understanding of how magnetic fields evolve in the solar atmosphere. A problem of great interest is the derivation of electric fields from vector magnetogram data, as this is the crucial link between observation and future physics-based time-dependent models of the solar atmosphere. Most previous techniques for deriving E have used only the normal component of the magnetic induction equation, as it is generally believed that depth derivatives contained in the magnetic induction equation cannot be derived from vector measurements taken within a single layer. I will show that in fact, sufficient information exists within a sequence of vector magnetograms to determine a 3-dimensional electric field whose curl reproduces the observed changes in all 3 components of B. While this is certainly a major step forward, it is still true that the electric field E itself, as opposed to its curl, is under-constrained by the data. I will discuss how additional considerations may be used to uniquely determine all 3 components of the electric field. | ||
| 17:40 - 18:00 | D. Mackay: Where do Solar Filaments Form? |
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| This paper examines the locations where large, stable solar filaments form relative to magnetic bipoles lying underneath them. The study extends the earlier work of F. Tang to include two additional classification categories for stable filaments and to consider their population during four distinct phases of the solar cycle. With this new classification scheme, results show that over 92% of filaments form in flux distributions that are non-bipolar in nature where the filament lies either fully (79%) or partially (13%) above a PIL external to any single bipole. Filaments which form within a single bipole (traditionally called Type-A) are not so common as previously thought. These results are a significant departure from those of F. Tang. We also demonstrate that only filaments which form along the external PIL lying between two bipoles (62% of the full sample, traditionally called Type-B) show any form of solar cycle dependence, where their number significantly increases with magnetic activity over the solar cycle. | ||
| Tuesday, December 9 | ||
| I | Thematic Session 4, Chair: Mason | |
| 09:00 - 09:50 | N. Arge: Solar Activity and the Solar Wind |
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| 09:50 - 10:10 | C. Deforest: Polar Plumes: what has changed since the last solar minimum? |
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| Polar plumes are among the simplest structures in the solar corona, yet they remain enigmatic. The launch of SOHO during the last solar minimum allowed the development of a coherent picture of plume formation, morphology and behavior, yet left several mysteries, including their possible role in the high speed solar wind. In the recent solar minimum several new developments have changed or refined this picture, including new models of plume formation, higher resolution instrumentation, and the use of coronal tomography to improve understanding of the 3-D structure of plumes. I will summarize recent observational developments and current problems related to the understanding of plumes and their relationship to the solar wind. | ||
| 10:10 - 10:30 | M. Velli: Coronal plumes and the fast solar wind |
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| 10:30 - 11:00 | BREAK | |
| II | Instrument Capabilities and the Optimization of Observing Sequences, Chair: Hudson |
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| 11:00 - 11:15 | T. Shimizu: Hinode mission status and observations |
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| 11:15 - 11:40 | J. Cirtain: Hinode's draft plan on flare and AR long-term observations |
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| 11:40 - 12:05 | Discussion topics | |
| 12:05 - 12:30 | G. Cauzzi: |
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Despite the added challenges of weather and atmospheric turbulence, ground-based instruments are, and will be, at the forefront of solar physics for high resolution imaging and spectropolarimetry, issues of large relevance in any study of magnetic activity.
I will illustrate the operation and perspectives of the Interferometric BIdimensional Spectrometer (IBIS) at the Dunn Solar Telescope, as an example of a versatile ground-based instrument that can address a variety of scientific topics and provide highly complementary information to space-based data. In particular, the availability of spectra acquired simultaneously over extended areas is proving a crucial asset to properly interpret and put into context observations obtained with more classical instruments, and to fully characterize the 3-D structure of the lower solar atmosphere. I will further describe recent attempts and results of coordinated "service-mode" observing periods with IBIS and Hinode. While service-mode scheduling is still seldom used in targeted ground-based solar observations, it represents a far more efficient mode of operations and is expected to be widely used on future large ground-based telescopes in order to maximize their scientific output. | ||
| 12:30 - 14:30 | LUNCH | |
| 14:30 - 16:00 | III | Working Groups |
| 16:00 - 17:00 | Poster Session(DEFG) & Coffee Break | |
| 17:00 - 18:30 | IV | Working Groups |
| Wednesday, December 10 | ||
| 09:00 - 10:30 | I | Working Groups |
| 10:30 - 11:00 | BREAK | |
| 11:00 - 12:30 | II | Working Groups |
| Afternoon | Free Afternoon | |
| 19:30-22:00? | Conference Reception & Banquet | |
| Thursday, December 11 | ||
| 09:00 - 10:30 | I | Working Groups |
| 10:30 - 11:00 | BREAK | |
| 11:00 - 12:30 | II | Working Groups |
| 12:30 - 14:30 | LUNCH | |
| 14:30 - 16:00 | III | Working Groups |
| 16:00 - 17:00 | Poster Session(BCHIJ) & Coffee Break | |
| 17:00 - 18:30 | IV | Working Groups |
| Friday, December 12 | 09:00 - 10:30 | I | Plenary: Panel discussion D,E,F,G (Brian Dennis, leader) |
| 10:30 - 11:00 | BREAK | |
| 11:00 - 12:30 | II | Plenary: Panel discussion B,C,H,I,J (Helen Mason, leader) |
| ~12:30 | End of Workshop | |