Solar polar fields dominate the large-scale structure of the corona during most of the solar cycle, and seem to be indicators -if not precursors- of the magnetic activity in the next cycle. On the other hand, the large-scale flows at high latitudes play an important role in flux transport dynamos, but are still poorly constrained by observations. Thus, the solar poles are the object of desire of helioseismologists, solar cycle forecasters and flux transport modelers alike. The caveat is that the physical properties at the poles are hard to characterise because of the weak nature of the magnetics fields and the almost unsurmountable projection effects as seen from the Earth’s vantage point. This session will review the advances in the measurement and understanding of solar polar fields and flows, and their connection to the Solar Cycle. It will also explore the benefits that will come from complementing SDO data with other new and existing observatories, in the advent of DKIST, PROBA2 and Solar Orbiter.
Plenary speaker: Sarah Gibson (HAO)
|11:30||Extreme ultraviolet Variability Experiment (EVE): Status and Recent Science Results||Woods, T||Invited Oral|
| ||Tom Woods and the SDO/EVE team|
| ||LASP, University of Colorado - Boulder|
| ||The SDO Extreme ultraviolet Variability Experiment (EVE) includes several channels to observe the solar extreme ultraviolet (EUV) spectral irradiance from 1 to 106 nm. These channels include the Multiple EUV Grating Spectrograph (MEGS) A, B, and P channels from the University of Colorado (CU) and the EUV SpectroPhometer (ESP) channels from the University of Southern California (USC). The EVE irradiance spectra are important for studying the solar impacts in Earth’s ionosphere and thermosphere. With SDO now being in its 8th year, long-term variability over solar cycle 24 can be studied in detail. And, despite being full-disk observations, the EVE spectra with its many different emissions from the corona, transition region, and chromosphere have proven to be valuable observations for studying flare variability as a function of wavelength and CME properties through coronal dimming. To maintain accurate calibrations for the EVE irradiance data products, there are underflight calibration rocket flights using the prototype EVE instrument, with the latest one being on 18 June 2018. The status of EVE instruments, calibrations, and data products, along with some recent EVE-related science results will be presented. |
|13:15||Beyond Flatland: A Star of Many Dimensions||Gibson, S||Invited Oral|
| ||Sarah Gibson|
| ||The more we have learned about the Sun, the more we can appreciate its essential complexity. Telescopes confirmed that it was not an unblemished sphere. Multi-wavelength observations revealed its structured atmosphere, and ever-higher resolution exposed its spectacular dynamics. Helioseismology penetrated its depths, and STEREO views gave us our first three-dimensional perspective. With Solar Orbiter we will finally leave our ecliptic bias behind and see the Sun from high latitudes. What will we see? And what could we see if future missions dwell at near-polar vantages, providing a synoptic view from above or below? The science enabled by such viewpoints is broad and deep, with potential both to finally fill known gaps in our understanding, and to reveal hitherto undiscovered aspects of the Sun and heliosphere.|
|13:45||The EUI instrument onboard Solar Orbiter: the EUV corona imaged differently||Berghmans, D||Oral|
| ||David Berghmans , Pierre Rochus , Frédéric Auchère , Louise Harra , Werner Schmutz , Udo Schühle |
| || Royal Observatory of Belgium (B),  Centre Spatial de Liège (B),  Institut d'Astrophysique Spatiale (F),  UCL-Mullard Space Science Laboratory (UK),  PMOD World Radiation Center (S),  MPI for Solar System Research (G)|
| ||The ESA Solar Orbiter mission is designed to determine how the Sun creates and controls the heliosphere. The spacecraft will bring a combination of in situ and remote sensing instruments out of the ecliptic (>30°) and close to the sun (0.3 solar-radii). The launch of Solar Orbiter is expected (not earlier than) Feb 2019. The Extreme Ultraviolet Imager is part of the remote-sensing package of Solar Orbiter, to be operating during 3 ten-day periods of each orbit around the Sun, which last roughly half a year. These 3 periods will correspond to perihelion and maximal solar latitude north and south. The Extreme Ultraviolet Imager is itself a suite of three UV and EUV telescopes that observe the solar atmosphere both globally as well as at very high resolution.
The two high-resolution imagers (HRIs) will image the solar atmosphere in the chromospheric Lyman alpha line and the coronal 17nm pass band with a resolution of 0.5 arcsec. From perihelion, this will correspond to a pixel footprint on the solar disc of (110km)^2 . The Full Sun Imager (FSI), working at the 17.4 nm and 30.4 nm EUV passbands, will provide a global view of the solar atmosphere and is therefore an essential building block for the “connection science” of the Solar Orbiter mission. The FSI field of view is large enough (228arcmin) that, even at perihelion and at maximal off-points by Solar Orbiter, the full solar disk remains in the field of view. This large FOV and the FSI’s high sensitivity will allow to image the “transition corona” where the topology of streamers and pseudo-streamers fades in the solar wind. Furthermore, FSI will be the first to image all this from out of the ecliptic.
In this talk we will give an overview of the EUI instrument. We will focus on the novel aspects of EUI that will allow it to image beyond what previous EUV imagers could show us: EUV imaging from the highest solar latitude, with the widest field-of-view and at highest spatial resolution.|
|14:00||Solar EUV Irradiance Monitoring beyond SDO-EVE: GOES EXIS Preliminary Measurements and Validation||Eparvier, F||Oral|
| ||Francis Eparvier , Andrew Jones , Thomas Woods , Martin Snow , Edward Thiemann , William McClintock , Donald Woodraska , Janet Machol [2,3], Rodney Viereck , Thomas Eden , Steven Mueller , Randle Meisner |
| || University of Colorado - LASP,  University of Colorado - CIRES,  NOAA - NCEI,  NOAA - SWPC|
| ||Starting with the recently launched NOAA GOES-16, the future of solar extreme ultraviolet (EUV) and soft x-ray (XUV) irradiance monitoring for the next few decades will be with the EUV and X-Ray Irradiance Sensors (EXIS). EXIS consists of the X-Ray Sensor (XRS) and the EUV Sensor (EUVS). The updated XRS continues NOAA’s 40+ year history of flare observations in the 0.1-0.8 nm and 0.05-0.4 nm bands. The new EUVS design makes measurements of specific solar emission features that span the range of temperatures and variability in the source regions of EUV in the solar atmosphere, namely He II 25.6 nm, Fe XV 28.4 nm, He II 30.4 nm, C III 117.5 nm, H I Ly-alpha 121.6 nm, C II 133.5 nm, Si IV / O IV 140.5 nm, and the Mg II C/W feature centered around 280 nm. This collection of measurements allows for the modeling of the full EUV spectrum (see the presentation by E.M.B. Thiemann, et al. for details of the model). This presentation will give an overview of the preliminary measurements and data products from the GOES-16 and -17 EXIS instruments and comparisons and validations with other measurements (SDO-EVE, SORCE, TIMED-SEE and previous GOES). |
|14:15||The High-Resolution Coronal Imager 2.1||Rachmeler, L||Oral|
| ||Laurel A Rachmeler , Amy R Winebarger, Sabrina L Savage, Ken Kobayashi, and the rest of the Hi-C team.|
| ||NASA Marshall Space Flight Center|
| ||On May 29, 2018 the High-Resolution Coronal Imager successfully launched from White Sands Missile Range and gathered over five minutes of coronal images in the EUV. This Hi-C 2.1 version has been modified from the original instrument to observe at a peak wavelength of 17.2 nm, and includes a custom-build low-noise camera. The 260 x 260 arcsec FOV of Hi-C 2.1 targeted NOAA Active Region 12712 during this flight, and coordinated observations were taken with IRIS, XRT, EIS, AIA, and HMI as well as numerous ground-based telescopes. The primary science goals of Hi-C 2.1 are to study the coronal counterparts of type II spicules and explore the relationship between chromospheric and coronal heating in active region cores. We present an overview of the Hi-C 2.1 instrument and the data acquired during flight. |