Effect of Additional Magnetograph Observations From Different Lagrangian Points in Sun‐Earth System on Predicted Properties of Quasi‐Steady Solar Wind at 1 AU

A A Pevtsov,P Macneice,I I Virtanen,G Petrie

doi:10.1029/2020sw002448

Abstract

AbstractModeling the space weather conditions for a near‐Earth environment depends on a proper representation of magnetic fields on the Sun. There are discussions in the community with respect to the value of observations taken at several Lagrangian points (L1–L5) in the Sun‐Earth system. Observations from a single (e.g., Earth/L1) vantage point are insufficient to characterize rapid changes in magnetic field on the far side of the Sun. Nor can they represent well the magnetic fields near the solar poles. However, if the changes in sunspot activity were moderate, how well would our predictions of the solar wind based on a single viewing point work? How much improvement could we see by adding magnetograph observations from L5, L4, and even L3? Here, we present the results of our recent modeling, which shows the level of improvement in forecasting the properties of the solar wind at Earth made possible by using additional observations from different vantage points during a period of moderate evolution of sunspot activity. As an example, we also show the improvements to the solar wind forecast from adding a single observation of the southern polar area from out‐of‐ecliptic spacecraft at −30° heliographic latitude vantage point.

Highlights

Modeling the space weather conditions for a near‐Earth environment depends on an accurate representation of magnetic fields on the Sun
If the changes in sunspot activity were moderate, how well would our predictions of the solar wind based on a single viewing point work? How much improvement could we see by adding magnetograph observations from L5, L4, and even L3? Here, we present the results of our recent modeling, which shows the level of improvement in forecasting the properties of the solar wind at Earth made possible by using additional observations from different vantage points during a period of moderate evolution of sunspot activity
We show the effect from a hypothetical location of recently launched Solar Orbiter spacecraft (SolO, Müller et al, 2013) when it would be below the ecliptic plane at −30° heliographic latitude vantage point

Summary

Introduction

The Carrington (heliographic latitute‐longitude) coordinate system on the Sun is based on the assumption of a fixed period of solar rotation at the equator (mean synodic rotation is 27.2753 days), with the first CR starting 9 November 1853 (e.g., Thompson, 2006) Such CR synoptic charts are constructed over a full solar rotation (about 27 days), by adding new observations of a visible portion of solar disk to the observations taken in early periods (e.g., Bertello et al, 2014; Ulrich & Boyden, 2006, and references therein). The comparative studies of modeling outcomes with additional data from other vantage points are complicated by the fact that currently, there are no observations, which could represent “true” distribution of magnetic fields on the Sun. Petrie et al (2018) explored an alternative approach by employing artificial data. We show the effect from a hypothetical location of recently launched Solar Orbiter spacecraft (SolO, Müller et al, 2013) when it would be below the ecliptic plane at −30° heliographic latitude vantage point

Data and Models

Results

Conclusions