First Spacecraft to Touch the Sun Awaiting Launch

Solar physics is a historically data-starved science, but about to becomes less so. ‘The future of solar physics’ looks at new facilities, either online or about to come online, such as the Daniel K. Inouye Solar Telescope on Maui. This aims to see, through measurements of coronal magnetic fields and plasma, how the Sun’s magnetic fields generate flares, coronal mass ejections, and the solar wind. Other major missions include NASA’s Parker Solar Probe and the European Solar Orbiter mission, spacecraft intended to orbit the Sun in new ways and from different viewpoints on Earth. Supported by increasingly powerful computers, these missions are ushering in a new era.

Download Full-text

Open magnetic fields on the Sun and solar wind parameters at the Earth’s orbit

Astronomy Reports ◽

10.1134/s1063772911030048 ◽

2011 ◽

Vol 55 (3) ◽

pp. 284-291

Author(s):

V. N. Obridko ◽

B. D. Shelting ◽

I. M. Livshits

Keyword(s):

Solar Wind ◽

Magnetic Fields ◽

The Sun ◽

Solar Wind Parameters

Download Full-text

1. The Sun, our star

The Sun: A Very Short Introduction ◽

10.1093/actrade/9780198832690.003.0001 ◽

2020 ◽

pp. 1-41

Author(s):

Philip Judge

Keyword(s):

Solar Wind ◽

Magnetic Fields ◽

Electric Fields ◽

Coronal Mass Ejections ◽

The Sun ◽

Short History ◽

Plasma State ◽

History Of

‘The Sun, our star’ presents a short history of the Sun and its relationship with Earth. While our ancestors worshipped the Sun, we may now take it for granted. Alpha Centauri A, the nearest other Sun-like star, is four light years away, compared to the Sun’s eight light minutes. The Sun and stars are neither solid nor liquid but composed of ionized particles in a plasma state. This plasma can sustain magnetic fields but not electric fields. The Sun exhibits remarkable phenomena such as sunspots, the corona, flares, the solar wind, and coronal mass ejections. Its atmosphere is layered into photosphere, chromosphere, and corona.

Download Full-text

Three-dimensional MHD simulation of the 2008 December 12 coronal mass ejection: from the Sun to Interplanetary space

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2019034 ◽

2019 ◽

Vol 9 ◽

pp. A33

Author(s):

Man Zhang ◽

Xue Shang Feng ◽

Li Ping Yang

Keyword(s):

Solar Wind ◽

Magnetic Fields ◽

Coronal Mass Ejection ◽

Interplanetary Space ◽

Three Dimensional ◽

Finite Volume Scheme ◽

The Sun ◽

Dynamical Interaction ◽

Spherical Coordinate ◽

Mass Ejection

A three-dimensional time-dependent, numerical magnetohydrodynamic simulation is performed to investigate the propagation of a coronal mass ejection that occurred on 12 December 2008. The background solar wind is obtained by using a splitting finite-volume scheme based on a six-component grid system in spherical coordinate, with Parker’s one-dimensional solar wind solution and measured photospheric magnetic fields as the initial values. A spherical plasmoid is superposed on the realistic ambient solar wind to study the 12 December 2008 coronal mass ejection event. The plasmoid is assumed to have a spheromak magnetic structure with a high-density, high-velocity, and high-pressure near the Sun. The dynamical interaction between the coronal mass ejection and the background solar wind flow is then investigated. We compared the model results with observations, and the model provide a relatively satisfactory comparison with the Wind spacecraft observations at 1 AU. We also investigated the numerical results assuming different parameters of the CME, we find that initial magnetic fields in the CME have a larger influence on the solar wind parameters at the Earth.

Download Full-text

Solar wind electrons reflected by lunar electric and magnetic fields

Science China Earth Sciences ◽

10.1007/s11430-011-4211-4 ◽

2011 ◽

Vol 54 (11) ◽

pp. 1796-1800 ◽

Cited By ~ 2

Author(s):

YongYong Feng ◽

YiTeng Zhang ◽

Hua Zhao ◽

ZhenXing Liu

Keyword(s):

Solar Wind ◽

Magnetic Fields ◽

Electric And Magnetic Fields

Download Full-text

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

International Astronomical Union Colloquium ◽

10.1017/s0252921100064630 ◽

2000 ◽

Vol 179 ◽

pp. 263-264

Author(s):

K. Sundara Raman ◽

K. B. Ramesh ◽

R. Selvendran ◽

P. S. M. Aleem ◽

K. M. Hiremath

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Magnetic Flux ◽

Ultra Violet ◽

Active Regions ◽

Morphological Properties ◽

Energy Storage And Conversion ◽

The Sun ◽

X Rays ◽

The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

Download Full-text

Solar Filaments as Tracers of Subsurface Processes

International Astronomical Union Colloquium ◽

10.1017/s0252921100064459 ◽

2000 ◽

Vol 179 ◽

pp. 177-183

Author(s):

D. M. Rust

Keyword(s):

Magnetic Fields ◽

Magnetic Flux ◽

Coronal Mass Ejections ◽

Interplanetary Space ◽

Intermediate Stage ◽

Coronal Plasma ◽

Magnetic Helicity ◽

The Sun ◽

New Paradigm ◽

Solar Filaments

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

Download Full-text

The Interpretation of Line Profiles

International Astronomical Union Colloquium ◽

10.1017/s0252921100053318 ◽

1977 ◽

Vol 36 ◽

pp. 191-215

Author(s):

G.B. Rybicki

Keyword(s):

Magnetic Fields ◽

Atomic Physics ◽

Velocity Fields ◽

Spectral Lines ◽

Inhomogeneous Structure ◽

The Sun ◽

Line Profiles ◽

Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

Download Full-text