Space weather: From solar eruptions to magnetospheric storms

2006 ◽  
pp. 375-385 ◽  
Author(s):  
Hannu E. J. Koskinen ◽  
K. Emilia J. Huttunen
Keyword(s):  
Space Weather ◽  
Solar Eruptions

scholarly journals Predicting the geoeffective properties of coronal mass ejections: current status, open issues and path forward

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180096 ◽  
Author(s):  
A. Vourlidas ◽  
S. Patsourakos ◽  
N. P. Savani
Keyword(s):  
Space Weather ◽  
Coronal Mass Ejections ◽  
Technology Development ◽  
Action Plan ◽  
Current Status ◽  
Weather Impact ◽  
Solar Eruptions ◽  
Holding Back ◽  
Open Issues ◽  
Made In

Much progress has been made in the study of coronal mass ejections (CMEs), the main drivers of terrestrial space weather thanks to the deployment of several missions in the last decade. The flow of energy required to power solar eruptions is beginning to be understood. The initiation of CMEs is routinely observed with cadences of tens of seconds with arc-second resolution. Their inner heliospheric evolution can now be imaged and followed routinely. Yet relatively little progress has been made in predicting the geoeffectiveness of a particular CME. Why is that? What are the issues holding back progress in medium-term forecasting of space weather? To answer these questions, we review, here, the measurements, status and open issues on the main CME geoeffective parameters; namely, their entrained magnetic field strength and configuration, their Earth arrival time and speed, and their mass (momentum). We offer strategies for improving the accuracy of the measurements and their forecasting in the near and mid-term future. To spark further discussion, we incorporate our suggestions into a top-level draft action plan that includes suggestions for sensor deployment, technology development and modelling/theory improvements. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals Sources of solar energetic particles

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180095 ◽  
Author(s):  
Loukas Vlahos ◽  
Anastasios Anastasiadis ◽  
Athanasios Papaioannou ◽  
Athanasios Kouloumvakos ◽  
Heinz Isliker
Keyword(s):  
Solar Corona ◽  
Space Weather ◽  
Solar Flares ◽  
Large Scale ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Plasma Parameters ◽  
Current Sheets ◽  
Solar Eruptions ◽  
Magnetohydrodynamic Simulations

Solar energetic particles are an integral part of the physical processes related with space weather. We present a review for the acceleration mechanisms related to the explosive phenomena (flares and/or coronal mass ejections, CMEs) inside the solar corona. For more than 40 years, the main two-dimensional cartoon representing our understanding of the explosive phenomena inside the solar corona remained almost unchanged. The acceleration mechanisms related to solar flares and CMEs also remained unchanged and were part of the same cartoon. In this review, we revise the standard cartoon and present evidence from recent global magnetohydrodynamic simulations that support the argument that explosive phenomena will lead to the spontaneous formation of current sheets in different parts of the erupting magnetic structure. The evolution of the large-scale current sheets and their fragmentation will lead to strong turbulence and turbulent reconnection during solar flares and turbulent shocks. In other words, the acceleration mechanism in flares and CME-driven shocks may be the same, and their difference will be the overall magnetic topology, the ambient plasma parameters, and the duration of the unstable driver. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals Formation of a tiny flux rope in the center of an active region driven by magnetic flux emergence, convergence, and cancellation

2020 ◽  
Vol 642 ◽  
pp. A199
Author(s):  
Ruisheng Zheng ◽  
Yao Chen ◽  
Bing Wang ◽  
Hongqiang Song ◽  
Wenda Cao
Keyword(s):  
Active Region ◽  
Magnetic Flux ◽  
Space Weather ◽  
Source Region ◽  
Flux Rope ◽  
Negative Polarity ◽  
Flux Emergence ◽  
High Quality ◽  
Solar Eruptions ◽  
A Minor

Aims. Flux ropes are generally believed to be core structures of solar eruptions that are significant for the space weather, but their formation mechanism remains intensely debated. We report on the formation of a tiny flux rope beneath clusters of active region loops on 2018 August 24. Methods. Combining the high-quality multiwavelength observations from multiple instruments, we studied the event in detail in the photosphere, chromosphere, and corona. Results. In the source region, the continual emergence of two positive polarities (P1 and P2) that appeared as two pores (A and B) is unambiguous. Interestingly, P2 and Pore B slowly approached P1 and Pore A, implying a magnetic flux convergence. During the emergence and convergence, P1 and P2 successively interacted with a minor negative polarity (N3) that emerged, which led to a continuous magnetic flux cancellation. As a result, the overlying loops became much sheared and finally evolved into a tiny twisted flux rope that was evidenced by a transient inverse S-shaped sigmoid, the twisted filament threads with blueshift and redshift signatures, and a hot channel. Conclusions. All the results show that the formation of the tiny flux rope in the center of the active region was closely associated with the continuous magnetic flux emergence, convergence, and cancellation in the photosphere. Hence, we suggest that the magnetic flux emergence, convergence, and cancellation are crucial for the formation of the tiny flux rope.

scholarly journals PSTEP: project for solar–terrestrial environment prediction

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kanya Kusano ◽  
Kiyoshi Ichimoto ◽  
Mamoru Ishii ◽  
Yoshizumi Miyoshi ◽  
Shigeo Yoden ◽  
...  
Keyword(s):  
Space Weather ◽  
Summer School ◽  
Research Collaboration ◽  
Modern Society ◽  
Weather Forecast ◽  
Science Research ◽  
Terrestrial Environment ◽  
Sports Science ◽  
Operational Forecasts ◽  
Solar Eruptions

AbstractAlthough solar activity may significantly impact the global environment and socioeconomic systems, the mechanisms for solar eruptions and the subsequent processes have not yet been fully understood. Thus, modern society supported by advanced information systems is at risk from severe space weather disturbances. Project for solar–terrestrial environment prediction (PSTEP) was launched to improve this situation through synergy between basic science research and operational forecast. The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. By this project, we sought to answer the fundamental questions concerning the solar–terrestrial environment and aimed to build a next-generation space weather forecast system to prepare for severe space weather disasters. The PSTEP consists of four research groups and proposal-based research units. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

scholarly journals Solar Eruptions - the Effects on the Earth’s Environment

2002 ◽  
Vol 12 ◽  
pp. 384-388
Author(s):  
P. Brekke
Keyword(s):  
Space Weather ◽  
Coronal Mass Ejections ◽  
Solar Maximum ◽  
Space Environment ◽  
The Sun ◽  
Technological Systems ◽  
Heliospheric Observatory ◽  
Time Space ◽  
New Information ◽  
Solar Eruptions

AbstractThe response of our space environment to the constantly changing Sun is known as ”Space Weather”. The Solar and Heliospheric Observatory (SOHO) has obtained significant new information about coronal mass ejections (CMEs), the source of the most severe disturbances in the Earth’s environment. Most of the time space weather is of little concern in our everyday lives. However, when the space environment is disturbed by the variable outputs of the Sun, technologies that we depend on both in orbit and on the ground can be affected. The increasing deployment of radiation-, current-, and field-sensitive technological systems over the last few decades and the increasing presence of complex systems in space combine to make society more vulnerable to solar-terrestrial disturbances. Thus, our society is much more sensitive to space weather activity today compared to the last solar maximum. By observing the Sun 24 hours per day, SOHO has proved to be an important “space weather watchdog”. The importance of real-time monitoring of the Sun will be pointed out and a number of enterprises affected by space weather will be discussed.

A DEFT Way to Forecast Solar Flares

2021 ◽  
Vol 922 (2) ◽  
pp. 218
Author(s):  
Larisza D. Krista ◽  
Matthew Chih
Keyword(s):  
Space Weather ◽  
Solar Flares ◽  
Extreme Ultraviolet ◽  
Weather Forecast ◽  
Start Time ◽  
X Ray ◽  
Solar Observations ◽  
Solar Eruptions ◽  
Intensity Changes ◽  
Solar Ultraviolet

Abstract Solar flares have been linked to some of the most significant space weather hazards at Earth. These hazards, including radio blackouts and energetic particle events, can start just minutes after the flare onset. Therefore, it is of great importance to identify and predict flare events. In this paper we introduce the Detection and EUV Flare Tracking (DEFT) tool, which allows us to identify flare signatures and their precursors using high spatial and temporal resolution extreme-ultraviolet (EUV) solar observations. The unique advantage of DEFT is its ability to identify small but significant EUV intensity changes that may lead to solar eruptions. Furthermore, the tool can identify the location of the disturbances and distinguish events occurring at the same time in multiple locations. The algorithm analyzes high temporal cadence observations obtained from the Solar Ultraviolet Imager instrument aboard the GOES-R satellite. In a study of 61 flares of various magnitudes observed in 2017, the “main” EUV flare signatures (those closest in time to the X-ray start time) were identified on average 6 minutes early. The “precursor” EUV signatures (second-closest EUV signatures to the X-ray start time) appeared on average 14 minutes early. Our next goal is to develop an operational version of DEFT and to simulate and test its real-time use. A fully operational DEFT has the potential to significantly improve space weather forecast times.

scholarly journals Space Weather Related to Solar Eruptions With the ASO-S Mission

2020 ◽  
Vol 8 ◽  
Author(s):  
Li Feng ◽  
Weiqun Gan ◽  
Siqing Liu ◽  
Huaning Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Space Weather ◽  
Solar Eruptions

scholarly journals Introduction to the physics of solar eruptions and their space weather impact

2019 ◽  
Vol 377 (2148) ◽  
pp. 20190152 ◽  
Author(s):  
Vasilis Archontis ◽  
Loukas Vlahos
Keyword(s):  
Space Weather ◽  
Large Scale ◽  
Interplanetary Space ◽  
Active Regions ◽  
Solar Interior ◽  
Physical Processes ◽  
Weather Impact ◽  
Solar Eruptions ◽  
Earth Connection ◽  
Magnetic Disturbances

The physical processes, which drive powerful solar eruptions, play an important role in our understanding of the Sun–Earth connection. In this Special Issue, we firstly discuss how magnetic fields emerge from the solar interior to the solar surface, to build up active regions, which commonly host large-scale coronal disturbances, such as coronal mass ejections (CMEs). Then, we discuss the physical processes associated with the driving and triggering of these eruptions, the propagation of the large-scale magnetic disturbances through interplanetary space and the interaction of CMEs with Earth's magnetic field. The acceleration mechanisms for the solar energetic particles related to explosive phenomena (e.g. flares and/or CMEs) in the solar corona are also discussed. The main aim of this Issue, therefore, is to encapsulate the present state-of-the-art in research related to the genesis of solar eruptions and their space-weather implications. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals Ionospheric response to solar and interplanetary disturbances: a Swarm perspective

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180098 ◽  
Author(s):  
G. Balasis ◽  
C. Papadimitriou ◽  
A. Z. Boutsi
Keyword(s):  
Solar Cycle ◽  
Electric Fields ◽  
Space Weather ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Plasma Instabilities ◽  
Radio Communications ◽  
Weather Impact ◽  
Ionospheric Response ◽  
Solar Eruptions

The ionospheric response to solar and interplanetary disturbances has been the subject of intense study for several decades. For 5 years now, the European Space Agency's Swarm fleet of satellites surveys the Earth's topside ionosphere, measuring magnetic and electric fields at low-Earth orbit with unprecedented detail. Herein, we study in situ the ionospheric response in terms of the occurrence of plasma instabilities based on 2 years of Swarm observations. Plasma instabilities are an important element of space weather because they include irregularities like the equatorial spread F events, which are responsible for the disruption of radio communications. Moreover, we focus on three out of the four most intense geospace magnetic storms of solar cycle 24 that occurred in 2015, including the St Patrick's Day event, which is the strongest magnetic storm of the present solar cycle. We examine the associated ionospheric response at Swarm altitudes through the estimation of a Swarm Dst-like index. The newly proposed Swarm derived Dst index may be suitable for space weather applications. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals From solar sneezing to killer electrons: outer radiation belt response to solar eruptions

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180097 ◽  
Author(s):  
Ioannis A. Daglis ◽  
Christos Katsavrias ◽  
Marina Georgiou
Keyword(s):  
Electric Fields ◽  
Space Weather ◽  
High Speed ◽  
Radiation Belt ◽  
Interplanetary Space ◽  
Plasma Waves ◽  
Potential Hazard ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt ◽  
Solar Eruptions

Electrons in the outer Van Allen (radiation) belt occasionally reach relativistic energies, turning them into a potential hazard for spacecraft operating in geospace. Such electrons have secured the reputation of satellite killers and play a prominent role in space weather. The flux of these electrons can vary over time scales of years (related to the solar cycle) to minutes (related to sudden storm commencements). Electric fields and plasma waves are the main factors regulating the electron transport, acceleration and loss. Both the fields and the plasma waves are driven directly or indirectly by disturbances originating in the Sun, propagating through interplanetary space and impacting the Earth. This paper reviews our current understanding of the response of outer Van Allen belt electrons to solar eruptions and their interplanetary extensions, i.e. interplanetary coronal mass ejections and high-speed solar wind streams and the associated stream interaction regions.This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

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