As such, they represent one of the most important and interesting observational quantities that we can measure. In this talk, I will describe the state-of-the-art in stellar magnetic field diagnosis and modeling, focusing on recent results obtained for (non-degenerate) low-, intermediate- and high-mass stars. << Hide Extended Entry

The SEM-2 NOAA satellites also provided estimates of the auroral ion hemispheric power over the last 6 years. Daily median intersatellite correlations exceeded 70% most of the time after contamination or degradation issues were addressed, and the median daily values usually agreed within 5% overall after making baseline adjustments that ranged within a factor of two. Initial corrections were made to eliminate sunlight contamination, data dropouts over the auroral oval, the degradation of sensors over time, high spurious count rates, and increased noise at the end of a satellite lifetime. Adjustments were also made in most satellites such that the ratio of the south to north electron or total hemispheric power was approximately one over a year. The ratio of the concurrent median daily hemispheric power from both hemispheres shows that the winter values are about 25% higher than the summer values during solar maximum, and about 5% higher in solar minimum conditions. The winter/summer concurrent ratios of the ion hemispheric power are opposite to those of the electrons, showing increases in the summer to winter ratios of about 20% independent of solar cycle. Ions contribute most to the total hemispheric power, over 20%, in quiet conditions, and contribute a little over 10% for Kp 2 or more. Comparisons with imager estimates of the hemispheric power are fairly good, especially with maximum values during storms. Spectral power analyses of the hemispheric power and other geophysical indices were made to find the long and short time periodicities of the parameters. There are significant 27-day and 14-day periodicities in the hemispheric power associated with the solar rotation period. During solar minimum, there is also a very strong biannual periodicity due to summer/winter variations in the ionospheric conductance. The best cross-correlations were found to be with the Kp geomagnetic index for the electron hemispheric power and with the Ap geomagnetic index for the ion hemispheric power, with significant correlations in the long term with the solar wind velocity.
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It is important to know whether or not magnetic features are the only sources needed to account for the solar cycle variations. In this scenario, the magnetic network may have an important contribution, although it has not been fully quantified. We combine simultaneous magnetograms and intensity images from the MDI instrument on board the SOHO spacecraft to analyze the radiative properties of small photospheric magnetic elements. We determine the contrast of faculae and network elements as a function of position over the disk and magnetic field, and we find that these elements exhibit a very different contrast center-to-limb variation, implying that their contribution to irradiance variability is distinct. By extending this analysis through the rising phase of solar cycle 23, we conclude that the functional dependence of their contrast results to be time independent, implying that the physical properties of the underlying flux tubes may not vary with time. In an effort towards the quantification of the network contribution to long-term irradiance variations, we decompose magnetograms into two components and examine their properties along the solar cycle.
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It is reasonable to argue that a framework for advancing the study of solar and space physics has three main elements:

1. Understanding the basic underlying physical processes (such as magnetic reconnection, particle acceleration, etc.,) that dominate such systems;
2. Determining with high confidence the role of solar, ionospheric and magnetospheric processes in global climate change and atmospheric chemistry and dynamics; and
3. Understanding and predicting the space radiation environment for human and robotic exploration of the moon, Mars, and beyond (the Exploration Vision).

The first two of these framework elements, when developed substantially, will be "tranformational" in terms of their impact on astrophysics and Earth System science. The third element represents a key enabling capability to allow human exploration to proceed beyond low Earth orbit. Collaborative groups (such as the CISM consortium) are now working on grand syntheses of models and are striving for a true end-to-end modeling capability. The challenges of such integrated modeling are immense. Widely differing spatial and temporal scales must be accommodated and codes must be synchronized to a high degree. Much of the underlying physics at micro- and meso-scales remains unknown and many key interface regions must be treated using empirical or semi-empirical methods. New observations are essential to make progress in many of these problem areas and NASA has laid out a program of advanced observatories that will allow paradigm-altering measurements to be made. This talk describes the challenges and opportunities that lay before us in solar and space physics and addresses how this discipline can perhaps best contribute to NASA\'s Vision for Exploration.
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Due to their relatively rapid rotation and spectral peculiarities, measuring the fields on the surface of these stars has been quite difficult until the relatively recent advent of a number of high-resolution infrared spectrometers. From a stellar dynamo point of view, these young stars are interesting because they are fully convective, and therefore are not expected to have a solar-like interface dynamo. In this talk, I will review recent observations of the magnetic field strength and geometry on solar mass pre-main sequence stars. I will then review recent advances in theories of turbulent dynamos and compare model predictions of coronal and chromospheric emission with stellar observations.
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These observations offer the possibility of constraining the predictions of dynamo models, albeit indirectly. We will present the latest results from global inversions, and compare them with near-surface measurements from local helioseismology and direct Doppler measurements. Simulated inversion results, using artificial profiles, can be used to explore the limitations of the inversion methods; we will present some sample results from such an exercise.
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In the troposphere, UV radiation drives the chemistry that cleans the global atmosphere of most natural and anthropogenic pollutants, but is also an essential ingredient for the formation of urban smog. In the biosphere, direct exposure to UV radiation causes a variety of illnesses in humans and animals, and can damage both terrestrial and marine ecosystems - topics that have received much public attention since the issue of stratospheric ozone depletion came to light a few decades ago. Quantitative estimates of UV radiation are fairly straightforward but do require some attention to many factors that affect it: Solar spectral output, geometric parameters (Earth-sun distance and local solar zenith angle) scattering and absorption by atmospheric constituents (gases, aerosols, clouds), and properties of the lower boundary of the atmosphere (ground elevation, reflectivity). Estimates of impacts are more complex, requiring much additional information on the responses to UV radiation by different targets - be they atmospheric molecules or biota. I will present an overview of these various factors, and sensitivities to them, using the Tropospheric Ultraviolet Visible (TUV) model developed at NCAR. The source code (fortran77) is publicly available and is easily customized for use in different disciplines, e.g., atmospheric modeling, photochemistry, photobiology, or epidemiology.
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We summarize the properties of in situ CME observations and address constraints on CME initiation from these observations. We then focus on an event providing direct observations of filament material in the heliosphere. The interplanetary CME was caused by a spectacular filament eruption in early January 2005. We report on the overall magnetic topology of this event, and the compositional properties. We then put these results in the context of recent filament models by Rust, 2000 and Karpen et al., 2003.
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But the nature of the dark energy remains an enigma. In this talk I will describe the new physics and consequences of some of the various proposals --- quintessence, a Big Rip scenario, a gravitational phase transition, and new symmetries of nature.
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To accurately and efficiently simulate these phenomena and scales, scientists have long depended on representing the meteorological fields by the "Spectral Method" (SM), that is, expansion in a basis of smooth eigenfunctions such as spherical harmonics. SM is powerful in several respects, for example its accuracy improves exponentially with respect to the number N of basis functions. However SM is very inefficient in representing spatially localized phenomena, because the large N required to reduce artifacts implies a large number of grid points in regions where the fields are smooth, and therefore implies much wasted computational effort. This contrasts with the practice e.g., in aeronautical engineering, that uses the Finite-Element Method (FEM) with Adaptive Mesh Refinement (AMR) to deal with localized phenomena using variable-size grids, at the sacrifice of some local accuracy since the basis functions are typically very low-order and not smooth.

Results from two projects will be presented, starting with a generalization of nonlinear triadic interactions from their classic SM formulation for turbulence to a new wavelet formulation applied to localized coherent structures known as atmospheric blocking (AB) events. Whereas SM triads cannot distinguish AB from normal states, wavelet triads reveal localized energy and enstrophy cascades across scale, associated with AB. The second project, GASpAR, was carried out with collaborators in IMAGe and ESSL, building on results from the applied math community, to devise Spectral-Element Methods (SEM) that combine the best properties of SM (exponential convergence) and FEM-AMR (flexibility and high efficiency on 1000s of parallel processors). Results include simulation of 2D linear advection-diffusion and Burgers equation flows with dynamic AMR.
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In fact, recent results from both balloon and satellite measurements indicate strong losses that could empty the radiation belts in a day or less if no acceleration was taking place. Thus, quantifying and understanding losses is an important part of fully understanding radiation belt variability.

Balloon-based observations provide a method for studying relativistic electron losses through the observation of bremsstrahlung X-rays produced as the electrons precipitate into the atmosphere. Since balloons measure precipitation directly, such observations allow us to separate the effects of acceleration and loss. In addition, balloon offer a nearly-stationary platform from which the spatial scale, duration, and temporal variations of precipitation can be measured. This talk will review results from several balloon campaigns aimed at studying relativistic electron precipitation, including preliminary results from the MINIS multiple-balloon campaign conducted in January 2005.
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These small-scale waves, often transient and irregular, are important part of atmospheric dynamics and critical for numerical models to make reliable forecasts. Large-amplitude wave events, such that those generated by flow over mountains and convection, can produce extreme, hazard weathers downstream. As a friction to large-scale flow, gravity wave breaking may induce effective body forces at various altitudes that drive atmospheric circulation away from its radiative balance. Such forcing must be taken into account in large-scale numerical models for long-term predictions and the conditions on which atmospheric chemistry and climate are operated.

AIRS Radiance Perturbations 2.5 hPa, 14 Jan 2004, UT=16Z


AMSU-B C19 Radiance \~10 km, 14 Jan 2004, UT=5Z

I will present some recent results of gravity wave observations from advanced satellite instruments, including MLS, AMSU-A, AIRS, and GPS, and discuss the pros and cons associated with these observing techniques. It remains challenging for current satellite sensors to resolve every part of gravity wave spectra, but complementary sensitivities of these instruments begin to reveal valuable insights of wave generation, propagation and breakdown from a global perspective.
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• PANs are formed during the same process which produces tropospheric ozone, namely the photo-oxidation of hydrocarbons in the presence of nitrogen oxides (NOx). They are therefore excellent tracers of photochemical activity in an air mass and if more than one species of PANs can be measured, they can be used to learn about the specific mix of hydrocarbons responsible for local ozone production.
• PANs also constitute an important reservoir of reactive nitrogen in the atmosphere. Long-range transport of PANs can deliver reactive nitrogen to areas distant from primary NOx sources. Because the atmospheric lifetime of PANs strongly depends on temperature, they decompose in descending air masses as they warm up and release NOx. In remote places such as over the Pacific Ocean PANs can be the dominant source of NOx and profoundly alter the local photochemistry. Under the right circumstances, the slow thermal decomposition of PANs can extent the capacity of a polluted air mass to produce ozone for many days, beyond the chemical lifetime of NOx.

This presentation will give a brief overview of ozone production in the troposphere, the involvement of NOx, and the importance of atmospheric organic nitrogen compounds. The development of ever better measurement techniques to quantify them will also be emphasized.
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Farley-Buneman instability in the auroral ionosphere provides this lacking physics. This instability is believed to cause strong anomalous electron heating which affects the ionospheric conductivity. We use an earlier developed model of anomalous electron heating to estimate the ionospheric conductance disturbance as a function of the local electric field. This result is used to modify the ionospheric conductance in the LFM model to study its effect on the simulated transpolar potential. An idealized and real-case simulation is accomplished. In both cases, a considerable drop in the simulated transpolar potential is found. The latter is in a good agreement with the AMIE model and DMSP data
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Moreover, the p-mode parameters have been demonstrated to be very sensitive to the solar activity cycle.

To study the solar oscillations, ground-based networks and space-based instruments have been developed, with and without spatial resolution. These instruments have been acquiring data for at least one solar cycle, and the existence of these different databases has shown to be invaluable in improving our knowledge about the solar interior and in studying the manifestations of solar activity in the solar interior.

After a brief historic and presentation of all the different helioseismic instruments running today, I will present some observational results obtained with the full-disk, "Sun-as-a-star" Doppler velocity data from the IRIS++ ground-based network, and the evolution of the low-degree solar p-modes with solar activity. Contrary to full-disk data which are limited to the low degree modes, LOWL/ECHO, built and operated by HAO/NCAR, is an instrument with spatial resolution. LOWL/ECHO is optimized to observe low and intermediate degrees, so it can be used to probe all the solar interior, from the solar core to the surface. The scientific objectives of LOWL/ECHO will be presented, as well as the steps of the analysis process of such helioseismic data in order to estimate reliable mode parameters and measure accurate rotational splittings. << Hide Extended Entry

By measuring PMC’s and the thermal, chemical and dynamical environment in which they form, we will quantify the connection between these clouds and the meteorology of the polar mesosphere. The goal will be achieved by measuring PMC abundances, morphology, trends, particle size distributions and gravity wave effects and by conducting precise, vertical profile measurements of temperature, H2O, OH, CH4, O3, CO2, NO, and aerosols over the altitude range from 10 to 110 km depending on parameter. This mission will provide the basis for study of long-term mesospheric climate variability and its relationship to global change. AIM includes three instruments: SOFIE (Solar Occultation for Ice Experiment), an infrared solar occultation radiometer; CIPS (Cloud Imaging and Particle Size Experiment), a panoramic UV imager; and CDE (Cosmic Dust Experiment), an in-situ dust detector.
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The approach emphasizes the importance of localized and episodic events and treats these as discrete objects whose properties in simulations and observations can be compared. Some examples from short-term prediction models will be used to illustrate a general approach that can apply to whole-atmosphere genreal circulation and climate models.
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But with the increasing number of such planets (8 are known, as of last week), information is starting to dribble in. In this talk, I will describe the expected properties of these planetary atmospheres, the existing observations (including some significant upper limits), and the inferences that one may draw about physical conditions on these exotic objects. Along the way, I will take a short inspirational look at the planet Venus.
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We will discuss the progress in coupling to date and our plans for the future. In particular, we will describe the design philosophy and implementation of the CISM coupling framework and attempt to put it in context with other framework efforts, such as ESMF. The CISM approach has been to incorporate models with as little change to individual codes as possible, leaving stand-alone codes as separate executables. The coupling functions are left to intermediary processes which can take advantage of object-oriented techniques that aren't possible with the (usually) Fortran code of the base models. The CISM framework is built upon two software packages, InterComm and Overture. InterComm provides the communications channels between processes and the over-arching control structure. Overture provides grid overlap, grid interpolation, and variable translation functions; in coupling codes together data must be transferred from one grid to another, often with one physical variables being interpreted into another set. This approach leads to rather loose coupling and complementary to that taken by ESMF. It has advantages in distributed computing environments and inis development of coupled systems. ESMF has advantages for efficiency and tightly-coupled systems.
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Such coupled models aim to provide insight into the evolution of the magnetic field in the solar corona (and beyond), because they enable the study of magnetic fields embedded within a region that spans both high- and low-beta plasmas. In this talk, I will first present results from ongoing efforts to construct such models in both two and three dimensions using the compressible spherical segment (CSS) code, seeking to investigate the decay of localized magnetic bipoles having active-region length scales. I will then show results from our surface-flux transport model, in which magnetic bipoles of all sizes continually appear on and are advected across the model photosphere throughout a complete 22-year magnetic polarity cycle. The potential-field source-surface approximation is then used to determine the quiescent coronal magnetic field at each time step, from which the evolution of the coronal magnetic field topology and its effect on the heliospheric current sheet as a function of time can be investigated.
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Realistic magnetohydrodynamic simulations, including the effects of partial ionization and a fully non-local and frequency dependent radiative transfer, provide insight into the interaction of convective flows, radiation and magnetic fields in the photosphere whilst at the same time allowing a direct comparison with observations. In this talk, I report on a series of realistic local-box simulations carried out with MURaM, a MHD code designed for applications in the solar photosphere. After a brief description of the code, I will give an overview of a parameter study covering magneto-convection in the photosphere from quiet Sun to strong plage conditions and discuss structure, dynamics and photometric properties of photospheric magnetic fields, including the formation mechanism of G-Band bright points and the origin of the continuum contrast of faculae near the solar limb. Finally, I will present some results from a complementary line of simulations which addresses the decay of magnetic flux in regions of mixed polarity.
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That signature consists of brief intervals of accelerated or decelerated plasma flow within field reversal regions in which changes in the flow velocity and the magnetic field vector are correlated on one side and anti-correlated on the other. To date, we have identified more than 130 events of this nature in the plasma and magnetic field data from ACE and Ulysses. The special significance of the measurements is that 1) they demonstrate conclusively that quasi-stationary reconnection occurs relatively frequently in the solar wind far from the Sun; and 2) they optimally reveal the physical nature of Petschek-type reconnection exhausts. Here we provide a brief overview of insights gained from recent investigations of this phenomenon using the ACE and Ulysses data.
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The heated plasma cools by heat exchange with the ambient neutral gas. This should lead to vertical motion not unlike the convective activity in the troposphere. I will discuss some simulation results of heating in small-scale auroral filaments, incoherent scatter radar experiments of observing the effects of heating in auroral filaments, and a rocket experiment to observe the resulting vertical wind in the thermosphere.
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We have recently published FLUX, a fluxon model that can currently handle force-free field calculation in prescribed topology by relaxing a fluxon grid, and that is being augmented to study time-dependent systems in the presence of parametrized reconnection. FLUX grid points are much more expensive than conventional Eulerian grid cells, but they deliver good value: FLUX simulations of line-tied flux systems near the photosphere scale like 2-D models although they represent the full 3-D field. To my knowledge, FLUX is the first simulation code that is capable of solving nontrivial MHD stability problems in 3-D on a desktop workstation. We are beginning to use it to study CME onset, and other applications are pending. I will briefly discuss the theory, code, application, and roadmap for FLUX, and discuss how to download and run your own copy of the code.
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The equatorial anomaly is the most prominent feature in these maps and they show strong TEC variations with solar activity but relatively weak variations with geomagnetic activity in our three Kp bins. These maps also show the annual and semiannual anomalies, but lack the seasonal anomaly. As a final binning, three longitudinal bins (Indian, Pacific, and Atlantic) were added. The TEC measurements display strong longitudinal variations that closely follow the longitudinal variation of the magnetic declination. As a continuation of the study on the TEC measurements, a comprehensive comparison of the TOPEX TEC measurements with the recent version of the International Reference Ionosphere (IRI-2001) was performed. First, it was found that both the IRI and TOPEX TEC show a negligibly small geomagnetic dependency, regardless of the solar activity and seasonal conditions. For solar activity, however, not only the TECs from the IRI and TOPEX measurements, but also the difference between them, strongly depend on the solar activity. The comparison also shows that the daytime low-latitude ionosphere from the IRI always develops earlier than the corresponding TOPEX measurements. With respect to the longitudinal variations of TEC, the IRI TEC show good agreement with the TOPEX measurements for low solar activity, but for high solar activity, large discrepancies occur in the Pacific sector.
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In addition to providing high quality state estimates, ensemble filters also provide a sample of the probability distribution function of the state and are extremely easy to apply. In fact, it is possible to add an atmospheric GCM to a carefully crafted ensemble assimilation system with less than a week's worth of effort. This ease of development has led to a surge in applications making use of ensemble filters. The Data Assimilation Research Section of IMAGe provides a community facility for ensemble data assimilation called the Data Assimilation Research Testbed (DART). An overview of the key algorithms in DART including a novel algorithm for dealing with model error will be presented in a tutorial form. HAO scientists who may be curious about the potential of applying ensemble data assimilation to their models and/or observations should be able to gain an understanding of the capabilities and implementation challenges presented by a state-of-the-art ensemble facility.
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In this talk, I will discuss the central role that magnetic fields and MHD are believed to take in these processes. I will also discuss more speculative work on the possibility that magnetic fields can extract the rotational energy of a spinning black hole; indeed, this spinning black hole may well be a significant, but underappreciated, source of energy for many black-hole related phenomena.
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1) the reconnection topology problem, 2) the reconnection time scale problem. The topology problem arises from the fact that singular magnetic field structures (such as magnetic null lines and associated separatrix surfaces), which serve to unambiguously define reconnection in two dimensions, are structurally unstable in three dimensions. Nevertheless, we find that when the concept of "X line" is appropriately generalized, one can view dayside magnetopause reconnection as a familiar X line collapse process, in which the Chapman-Ferraro current sheet plays a role analogous to the Sweet-Parker current sheet in two-dimensional reconnection scenarios. This current sheet is associated with a magnetic separator line (a segment of a magnetic field line which extends across the dayside magnetopause, joining two clusters of cusp magnetic nulls) which is defined by the intersection of two separatrix surfaces. We find that it is possible to unify two competing hypothesis about the topology of magnetopause reconnection (the "antiparallel" and "component" reconnection hypotheses) in the context of separator reconnection. Nevertheless, the formation of the thin current sheet leads to a three-dimensional generalization of the two-dimensional Sweet-Parker time scale problem. We discuss the role of Hall electric fields in mitigating this time scale problem without the need to invoke anomalous plasma resistivity or Petschek slow mode shocks.
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Despite its widespread nature, the standard treatment of convection in stellar models is based on the ad hoc mixing length theory, in which the parameter "alpha" is freely adjustable. In this talk, I employ a new technique for fitting the light curves of pulsating white dwarfs which can place tight constraints on the depth of their convection zones, and I show how these results compare with those of standard mixing length theory. As a bonus, these fits also help us constrain the quantum numbers of the pulsation modes, which can aid us in the "asteroseismology" of the star's interior structure. I also discuss possible alternatives to mixing length theory, from hydrodynamic simulations to approaches involving a Reynolds Stress formalism.
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From this chromospheric network magnetic funnels emerge, and rapidly expand with height through the transition region and finally fill the whole corona. In this context, the role of the magnetic field for intensity enhancements and in velocity variations is still not clear. We examined the properties of emission line profiles as found with large raster scans of the solar corona acquired with the UV spectrometer SUMER on board SOHO. We establish that the maximum outflow at low corona temperatures does not appear in the center of the network but rather near network boundaries. To study the properties of such magnetic funnels and the role of the coronal heating, we employed a new 2D MHD time dependent model including the solar atmosphere all the way from the chromosphere to the corona. The energetic of the plasma includes radiative losses, thermal conduction and two different prescribed heating terms. We put special emphasis on the plasma flow out of the coronal funnel. We obtained 2D plasma properties (e.g. density, temperature, pressure and flow speed) within the funnel for each heating function. From the results of the MHD calculation, we derive spectral profiles of a low corona emission line (Ne VIII, 770 A). This allows us, e.g., to study the Doppler shifts across the funnel and thus enables a detailed comparison of model results with observations. These results indicate that the maximum outflow is not to be found in the very center of the funnel but in the vicinity of the center for one of the heating function; this is not the case of the second. The model directly relates, for the first time, the form of the heating function to the thermodynamic and spectral properties of the plasma in a funnel.
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With monthly zonal means, OH can be measured down to 20 km and the HO₂ can be measured over 26-60 km. Both measurements have been validated in September, 2004 using the balloon-borne BOH and FIRS-2 instruments. Data will be presented concerning the HO_x dilemma in the upper stratosphere and mesosphere. One interesting feature of night-time observations is a narrow layer of OH at 82 km that persists during the night and leads to catalytic destruction of O₃ at the same altitude. This layer is also related to the Meinel-band emission in the near infrared. The layer can even be observed in the polar night and its presence is evidence of meridianal transport of HO_x from sunlit latitudes. A second striking discovery is the observation of OH produced by a solar proton event in January 17-22, 2004. The enhanced OH can be seen at both poles and leads to temporary O₃ destruction in the polar night.
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However the physical mechanism behind facular brightening was until recently not understood and measurements of the center-to-limb variation of facular brightening used in irradiance models varied widely. We present new very high resolution (0.1 arcsecond) filtergram and magnetogram measurements of faculae taken with the Swedish 1-meter Solar Telescope on La Palma that show clearly that faculae are granules imaged through the reduced opacity caused by small-scale "magnetic elements" in the plage regions around sunspots. Facular brightening corresponds exactly with magnetic flux locations in the photosphere and extends in the radial direction, on average, for 400 km. This is significantly larger than the typical "Wilson depression" of 150--300 km calculated for 200 km wide flux sheets and argues against the traditional explanation of facular brightening being due to "hot wall" radiation from hypothetical flux tube interiors. Compressible 3D MHD simulations confirm that the majority of facular brightening comes from granulation "behind" magnetic elements and micropores. The findings argue for new models of facular irradiance based not on empirical flux tube models but on the properties of granules seen through varying amounts of magnetic flux across the disk.