Solar Stereoscopy and Tomography

Aschwanden, Markus J.

doi:10.12942/lrsp-2011-5

Cited by 51 publications

(56 citation statements)

References 229 publications

(328 reference statements)

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“…This paper highlights some key results obtained on the variable phenomena in the Sun-Earth system during the CAWSES-II time frame. Detailed treatment of topics relevant to CAWSES-II can be found in the Living Reviews in Solar Physics: Hathaway (2010), Charbonneau (2010), Petrovay (2010), Chen (2011), Shibata and Magara (2011), Aschwanden (2011), Webb and Howard (2012), Usoskin (2013), Potgieter (2013), Lockwood (2013), Owens and Forsyth (2013).…”

Section: Methodsmentioning

confidence: 99%

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Gopalswamy

Tsurutani

Yan

2015

Prog. in Earth and Planet. Sci.

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This paper presents an overview of results obtained during the CAWSES-II period on the short-term variability of the Sun and how it affects the near-Earth space environment. CAWSES-II was planned to examine the behavior of the solar-terrestrial system as the solar activity climbed to its maximum phase in solar cycle 24. After a deep minimum following cycle 23, the Sun climbed to a very weak maximum in terms of the sunspot number in cycle 24 (MiniMax24), so many of the results presented here refer to this weak activity in comparison with cycle 23. The short-term variability that has immediate consequence to Earth and geospace manifests as solar eruptions from closed-field regions and high-speed streams from coronal holes. Both electromagnetic (flares) and mass emissions (coronal mass ejections -CMEs) are involved in solar eruptions, while coronal holes result in high-speed streams that collide with slow wind forming the so-called corotating interaction regions (CIRs). Fast CMEs affect Earth via leading shocks accelerating energetic particles and creating large geomagnetic storms. CIRs and their trailing high-speed streams (HSSs), on the other hand, are responsible for recurrent small geomagnetic storms and extended days of auroral zone activity, respectively. The latter leads to the acceleration of relativistic magnetospheric 'killer' electrons. One of the major consequences of the weak solar activity is the altered physical state of the heliosphere that has serious implications for the shock-driving and storm-causing properties of CMEs. Finally, a discussion is presented on extreme space weather events prompted by the 23 July 2012 super storm event that occurred on the backside of the Sun. Many of these studies were enabled by the simultaneous availability of remote sensing and in situ observations from multiple vantage points with respect to the Sun-Earth line.

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Section: Methodsmentioning

confidence: 99%

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Gopalswamy

Tsurutani

Yan

2015

Prog. in Earth and Planet. Sci.

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“…Physical properties can be then derived from these multi-wavelength emissivities. Tomography is a highly underdetermined problem (Aschwanden, 2011), and the intrinsic difficulties of non-robustness and non-uniqueness of the solution have to be overcome. SRT in particular is further complicated by the lack of simultaneous viewpoints, which is limited by the number and location of available spacecraft.…”

Section: Introductionmentioning

confidence: 99%

Lifecycle of a Large-Scale Polar Coronal Pseudostreamer/Cavity System

Guennou

Rachmeler

Seaton

et al. 2016

Front. Astron. Space Sci.

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We report on an exceptional large-scale coronal pseudostreamer/cavity system in the southern polar region of the solar corona that was visible for approximately a year starting in February 2014. It is unusual to see such a large closed-field structure embedded within the open polar coronal hole. We investigate this structure to document its formation, evolution and eventually its shrinking process using data from both the PROBA2/SWAP and SDO/AIA EUV imagers. In particular, we used EUV tomography to find the overall shape and internal structure of the pseudostreamer and to determine its 3D temperature and density structure using DEM analysis. We found that the cavity temperature is extremely stable with time and is essentially at a similar or slightly hotter temperature than the surrounding pseudostreamer. Two regimes in cavity thermal properties were observed: during the first 5 months of observation, we found lower density depletion and highly multi-thermal plasma, while after the pseudostreamer became stable and slowly shrank, the depletion was more pronounced and the plasma was less multithermal. As the thermodynamic properties are strongly correlated with the magnetic structure, these results provide constraints on both the trigger of CMEs and the processes that maintain cavities stability for such a long lifetime.

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“…Less obvious, but of increasing interest is the capability of space telescopes to observe the Sun from a different vantage point, offering complementary views on our star. The Stereo mission has impressively demonstrated the advantages of stereoscopic viewing (Harrison et al 2009;Aschwanden 2011). Of particular interest are observations of the solar polar regions, which can be obtained from the ecliptic with only marginal quality (up to 7degrees, thanks to the inclination of the solar rotation axis).…”

Section: Advantages and Disadvantages Of Ground-and Space-based Telesmentioning

confidence: 99%

“…It is no longer available at THEMIS, but a new version is operating at the Meudon Observatory. TUNIS (Tunable Universal Narrowband Imaging Spectrograph) (López Ariste et al 2010, 2011 was developed after MSDP's idea and expanded through a so-called Hadamard mask, encoding full spectral information in the images. After 63 measurements shifting the Hadamard mask to predefined positions, the cube of x, y, λ can be reconstructed, making it a fast instrument compared to regular scanning spectrographs, for example.…”

Section: Themismentioning

confidence: 99%

Prospects of Solar Magnetometry—From Ground and in Space

Kleint¹,

Gandorfer²

2015

Space Sci Rev

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In this review we present an overview of observing facilities for solar research, which are planned or will come to operation in near future. We concentrate on facilities, which harbor specific potential for solar magnetometry. We describe the challenges and science goals of future magnetic measurements, the status of magnetic field measurements at different major solar observatories, and provide an outlook on possible upgrades of future instrumentation.

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Solar Stereoscopy and Tomography

Cited by 51 publications

References 229 publications

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Lifecycle of a Large-Scale Polar Coronal Pseudostreamer/Cavity System

Prospects of Solar Magnetometry—From Ground and in Space

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