The Possible Impact of L5 Magnetograms on Non-Potential Solar Coronal Magnetic Field Simulations

Weinzierl, Marion; Mackay, D. H.; Yeates, Anthony R.; Pevtsov, Alexei A.

doi:10.3847/0004-637x/828/2/102

Cited by 17 publications

(13 citation statements)

References 40 publications

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“…On the real Sun, the magnetic flux will change in other places, and thus, the difference in large‐scale connectivity should also be expected. These large‐scale effects were recently demonstrated by Weinzierl et al [] using the same data set as this paper.…”

Section: Discussion and Summarysupporting

confidence: 82%

What if we had a magnetograph at Lagrangian L5?

et al. 2016

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Synoptic Carrington charts of magnetic field are routinely used as an input for modelings of solar wind and other aspects of space weather forecast. However, these maps are constructed using only the observations from the solar hemisphere facing Earth. The evolution of magnetic flux on the “farside” of the Sun, which may affect the topology of coronal field in the “nearside,” is largely ignored. It is commonly accepted that placing a magnetograph in Lagrangian L5 point would improve the space weather forecast. However, the quantitative estimates of anticipated improvements have been lacking. We use longitudinal magnetograms from the Synoptic Optical Long‐term Investigations of the Sun (SOLIS) to investigate how adding data from L5 point would affect the outcome of two major models used in space weather forecast.

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Section: Discussion and Summarysupporting

confidence: 82%

What if we had a magnetograph at Lagrangian L5?

et al. 2016

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“…For example, a future space weather mission at L5 or L4 as a second coronagraph viewpoint would reduce CME arrival time errors compared to a single L1 viewpoint. For example, Akioka et al (2005), Simunac et al (2009), Gopalswamy et al (2011), Strugarek, Antoine et al (2015, Vourlidas (2015), Lavraud et al (2016), and Weinzierl et al (2016) all identify the potential benefit of an L5 mission. Lavraud et al (2016) proposes an L5 mission that would measure the coronal magnetic field using a polarization technique, in addition to white-light imaging.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…Lavraud et al (2016) proposes an L5 mission that would measure the coronal magnetic field using a polarization technique, in addition to white-light imaging. Weinzierl et al (2016) shows how an L5 mission equipped with a magnetic imager could improve predictions of solar wind, which is particularly important for the WSA-ENLIL+Cone model.…”

Section: Summary and Discussionmentioning

confidence: 99%

Verification of real-time WSA−ENLIL+Cone simulations of CME arrival-time at the CCMC from 2010 to 2016

Wold

Mays

Taktakishvili

et al. 2018

J. Space Weather Space Clim.

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The Wang-Sheeley-Arge (WSA)-ENLIL+Cone model is used extensively in space weather operations world-wide to model CME propagation. As such, it is important to assess its performance. We present validation results of the WSA-ENLIL+Cone model installed at the Community Coordinated Modeling Center (CCMC) and executed in real-time by the CCMC space weather team. CCMC uses the WSA-ENLIL+Cone model to predict CME arrivals at NASA missions throughout the inner heliosphere. In this work we compare model predicted CME arrival-times to in-situ ICME leading edge measurements at STEREO-A, STEREO-B, and Earth (Wind and ACE) for simulations completed between March 2010-December 2016 (over 1,800 CMEs). We report hit, miss, false alarm, and correct rejection statistics for all three locations. For all predicted CME arrivals, the hit rate is 0.5, and the false alarm rate is 0.1. For the 273 events where the CME was predicted to arrive at Earth, STEREO-A, or STEREO-B, and was actually observed (hit event), the mean absolute arrival-time prediction error was 10.4±0.9 hours, with a tendency to early prediction error of -4.0 hours. We show the dependence of the arrival-time error on CME input parameters. We also explore the impact of the multi-spacecraft observations used to initialize the model CME inputs by comparing model verification results before and after the STEREO-B communication loss (since September 2014) and STEREO-A sidelobe operations (August 2014-December 2015. There is an increase of 1.7 hours in the CME arrival time error during single, or limited twoviewpoint periods, compared to the three-spacecraft viewpoint period. This trend would apply to a future space weather mission at L5 or L4 as another coronagraph viewpoint to reduce CME arrival time errors compared to a single L1 viewpoint.

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“…Therefore a more accurate treatment must be developed. Techniques that allow for the direct assimilation of normal component magnetograms across all longitudes and latitudes are under development and testing (see Weinzierl et al 2016a andWeinzierl et al 2016b). One issue with the direct assimilation of magnetogram data into the simulation, is that only a portion of the global photospheric field may be observed at any given time.…”

Section: Producing An Operational Modelmentioning

confidence: 99%

A new technique for observationally derived boundary conditions for space weather

Pagano

Mackay

Yeates

2018

J. Space Weather Space Clim.

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-Context. In recent years, space weather research has focused on developing modelling techniques to predict the arrival time and properties of coronal mass ejections (CMEs) at the Earth. The aim of this paper is to propose a new modelling technique suitable for the next generation of Space Weather predictive tools that is both efficient and accurate. The aim of the new approach is to provide interplanetary space weather forecasting models with accurate time dependent boundary conditions of erupting magnetic flux ropes in the upper solar corona. Methods. To produce boundary conditions, we couple two different modelling techniques, MHD simulations and a quasi-static non-potential evolution model. Both are applied on a spatial domain that covers the entire solar surface, although they extend over a different radial distance. The non-potential model uses a time series of observed synoptic magnetograms to drive the non-potential quasi-static evolution of the coronal magnetic field. This allows us to follow the formation and loss of equilibrium of magnetic flux ropes. Following this a MHD simulation captures the dynamic evolution of the erupting flux rope, when it is ejected into interplanetary space. Results.The present paper focuses on the MHD simulations that follow the ejection of magnetic flux ropes to 4 R ⊙ . We first propose a technique for specifying the pre-eruptive plasma properties in the corona. Next, time dependent MHD simulations describe the ejection of two magnetic flux ropes, that produce time dependent boundary conditions for the magnetic field and plasma at 4 R ⊙ that in future may be applied to interplanetary space weather prediction models. Conclusions. In the present paper, we show that the dual use of quasi-static non-potential magnetic field simulations and full time dependent MHD simulations can produce realistic inhomogeneous boundary conditions for space weather forecasting tools. Before a fully operational model can be produced there are a number of technical and scientific challenges that still need to be addressed. Nevertheless, we illustrate that coupling quasi-static and MHD simulations in this way can significantly reduce the computational time required to produce realistic space weather boundary conditions.

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The Possible Impact of L5 Magnetograms on Non-Potential Solar Coronal Magnetic Field Simulations

Cited by 17 publications

References 40 publications

What if we had a magnetograph at Lagrangian L5?

What if we had a magnetograph at Lagrangian L5?

Verification of real-time WSA−ENLIL+Cone simulations of CME arrival-time at the CCMC from 2010 to 2016

A new technique for observationally derived boundary conditions for space weather

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