Solar Magnetic Field Research Papers (original) (raw)

The solar dynamo continues to pose a challenge to observers and theoreticians. Observations of the solar surface reveal a magnetic field with a complex, hierarchical structure consisting of widely different scales. Systematic features such as the solar cycle, the butterfly diagram, and Hale's polarity laws point to the existence of a deep-rooted large-scale magnetic field. At the other end of the scale are magnetic elements and small-scale mixed-polarity magnetic fields. In order to explain these phenomena, dynamo theory provides all the necessary ingredients including the alpha\alphaalpha effect, magnetic field amplification by differential rotation, magnetic pumping, turbulent diffusion, magnetic buoyancy, flux storage, stochastic variations and nonlinear dynamics. Due to advances in helioseismology, observations of stellar magnetic fields and computer capabilities, significant progress has been made in our understanding of these and other aspects such as the role of the tachocline, convective plumes and magnetic helicity conservation. However, remaining uncertainties about the nature of the deep-seated toroidal magnetic field and the alpha\alphaalpha effect, and the forbidding range of length scales of the magnetic field and the flow have thus far prevented the formulation of a coherent model for the solar dynamo. A preliminary evaluation of the various dynamo models that have been proposed seems to favor a buoyancy-driven or distributed scenario. The viewpoint proposed here is that progress in understanding the solar dynamo and explaining the observations can be achieved only through a combination of approaches including local numerical experiments and global mean-field modeling.

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- Astrophysics, Astronomy, Dynamo theory, Solar Magnetic Field
- by D. Maia
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- X Rays, Coronal Mass Ejection, Space Weather, Solar Energetic Particle Events

The variability of the Sun's magnetic field is the main driver of solar activity. IAU S233 was held to further our understanding about solar magnetic processes and also its interplanetary consequences. The Symposium was organized... more

- by Ahmed Hady
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- Physics, Magnetic field, Solar Activity, Graduate Student

When a land-air misile is fired to pursuit a mobil target, quite a few variables play a key role in order to reach and neutralise the target in no-time. It is desired; nevertheless, this system requires an amount of time, fuel, real-time data analysis as well as a discriminator system, all these in order to reach the mobil target. This is why, in this work we present a study for a set of variables meassured in situ such as: the wind speed, magnetic field, pressure and humidity to generate logs that can be usuful for either civil and militar applications. The system is designed to meassure in situ a set of variables starting at 500 m up to 30 km. As a result of this study, all the information gathered can be feed into the missil main computer and with the info loaded, it can trace trajectories in which the efficiency of the engine, fuel and cargo reach the target. The low atmosphere system has the follow set of instruments: a barometer, accelerometer, gyroscope and a magnetometer as the sensor array. We are using an Intel Galileo board as the motherboard. The information collected is saved within a SD high density memory card.

- by Mario Alberto García-Ramírez and +2
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- Embedded Systems, Magnetic field, Solar Magnetic Field, Gravity Measurements
- by Mathieu Ossendrijver
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- Magnetohydrodynamics, Dynamo theory, Solar Magnetic Field, Maunder Minima
- by Chris Davis
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- Earth Sciences, Magnetic field, Physical sciences, Solar Wind
- by H. Hudson
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- X Rays, Coronal Mass Ejection, Space Weather, Solar Energetic Particle Events
- by Igor Sokolov
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- Organic Chemistry, Magnetohydrodynamics, Astrophysical Plasma, Magnetic field
- by Adriana Silva
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- Organic Chemistry, Astrophysical Plasma, X Rays, Terahertz

The main features of solar cycle 23, sun enters a period of intermediate and weak solar activity in terms of sunspot number. Based on the observation from Omniweb data centre for solar- interplanetary data , geomagnetic activity and monthly mean count rate of cosmic ray intensity (CRI) variation data from Oulu / Moscow/ Keil neutron monitors (Rc=0.80 GV , Rc=2.42 GV and Rc=2.29 GV,) during solar activity cycle 23 . The phase of minimum solar activity began in May 2005 and lasted for 4.5 years the unprecedented duration of the relative sunspot numbers falls. It is observed that the strength of the interplanetary magnetic field has been falling off to new low levels, and reduces the GCR entering inner- heliosphere and it is also found that SSN positive correlated with Kp and Ap and sunspot number, 10.7 cm solar radio flux, were inverse correlated with monthly mean count rate of cosmic ray intensity

- by Volker Bothmer
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- Physics, Magnetic field, Solar Activity, Graduate Student
- by Mar Isd
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- Data Analysis, Interplanetary dust, Multidisciplinary, Solar Magnetic Field

The SUNRISE balloon project is a high-resolution mission to study solar magnetic fields able to resolve the critical scale of 100 km in the solar photosphere, or about one photon mean free path. The Imaging Magnetograph eXperiment (IMaX) is one of the three instruments that will fly in the balloon and will receive light from the 1m aperture telescope of the mission. IMaX should take advantage of the 15 days of uninterrupted solar observations and the exceptional resolution to help clarifying our understanding of the small-scale magnetic concentrations that pervade the solar surface. For this, IMaX should act as a diffraction limited imager able to carry out spectroscopic analysis with resolutions in the 50.000-100.000 range and capable to perform polarization measurements. The solutions adopted by the project to achieve all these three demanding goals are explained in this article. They include the use of Liquid Crystal Variable Retarders for the polarization modulation, one LiNbO3 etalon in double pass and two modern CCD detectors that allow for the application of phase diversity techniques by slightly changing the focus of one of the CCDs.

- by Juan A Medina Ruiz
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- Proceedings, Solar Magnetic Field, High Resolution, Liquid Crystal
- by Ingrid Mann
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- Geochemistry, Geophysics, Solar Activity, Solar Magnetic Field

3He-rich solar energetic particles (SEPs), showing up to a 10,000-fold abundance enhancement of rare elements like 3He or ultra-heavy nuclei, have been a puzzle for more than 50 years. One reason for the current lack of understanding of 3He-rich SEPs is the difficulty resolving the source regions of these commonly occurring events. Since their discovery, there has been strong evidence that 3He-rich SEP production is associated with flares on the Sun. Anomalous abundances of 3He-rich SEPs have been attributed to a unique acceleration mechanism that must routinely operate at flare sites. Flares associated with 3He-rich SEPs have been often observed in jet-like forms indicating an acceleration in magnetic re-connection involving field lines open to interplanetary space. Owing to a fleet of spacecraft around the Sun, providing a greatly improved resolution of solar imaging observations, 3He-rich SEP sources are now explored in unprecedented detail. This paper outlines the current understanding of 3He-rich SEPs, mainly focusing on their solar sources.

- by Mathieu Ossendrijver
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- Magnetohydrodynamics, Dynamo theory, Solar Magnetic Field, Maunder Minima

Analysis of Pioneer V engulfment with solar plasma on March 30, 1960, showed that solar magnetic field was not detected by the probe, rather a high interplanetary magnetic field (IMF) was later measured after first been recorded by Honolulu earth station; this questioned envisioned embedded solar magnetic field. A proposed mechanism of solar wind captured at and before the bow shock, producing Interplanetary-External Magnetic Field (I-ExMF), led to energization of these particles; while boundaries between IMF represent space between intermittent produced I-ExMF. Intense I-ExMF (II-ExMF) is produced around 12.5R E within magnetosheath, igniting transitory magnetic waves (lion roars); initiating the sudden commencement and related main phase. Explanation of these, and the propagation of magnetic disturbances and the interplanetary sector structure, is based on I-ExMF characteristics. Understanding these mechanisms will reflect positively on attaining the alternative renewable green energy that can protect our planet, environment and establishment of more advanced human society.

We studied the relationship between the projected speed of coronal mass ejections (CMEs), determined from a sequence of Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment (SOHO/LASCO) images, and the hourly averaged magnitude of the Bz component of the magnetic field in an interplanetary ejecta, as measured by the Advanced Composition Explorer (ACE) magnetometer in the Geocentric Solar Magnetospheric Coordinate System (GSM). For CMEs that originate at the central part of the solar disk we found that the intensity of Bz is correlated with the projected speed of the CME, Vp. The relationship is more pronounced for very fast ejecta (Vp > 1200 km/s), while slower events display larger scatter. We also present data which support earlier conclusions about the correlation of Bz and the Dst index of geomagnetic activity. A possible application of the results to space weather forecasting is discussed.

- by Vasyl Yurchyshyn
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- Magnetic field, Coronal Mass Ejection, Space Weather, Solar Magnetic Field
- by Mathieu Ossendrijver
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- Magnetohydrodynamics, Chaos Theory, Astrophysics, Dynamo theory
- by Jose W F Valle
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- Mathematical Physics, Quantum Physics, Magnetohydrodynamics, Electronic Spectra
- by Attila Grandpierre
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- Solar Physics, Solar Magnetic Field, Energy Production, Solar Flare

The instrument SUMER - Solar Ultraviolet Measurements of Emitted Radiation is designed to investigate structures and associated dynamical processes occurring in the solar atmosphere, from the chromosphere through the transition region to the inner corona, over a temperature range from 104 to 2 × 106K and above. These observations will permit detailed spectroscopic diagnostics of plasma densities and temperatures in many solar features, and will support penetrating studies of underlying physical processes, including plasma flows, turbulence and wave motions, diffusion transport processes, events associated with solar magnetic activity, atmospheric heating, and solar wind acceleration in the inner corona. Specifically, SUMER will measure profiles and intensities of EUV lines; determine Doppler shifts and line broadenings with high accuracy; provide stigmatic images of the Sun in the EUV with high spatial, spectral, and temporal resolution; and obtain monochromatic maps of the full Sun and the inner corona or selected areas thereof. SUMER will be flown on the Solar and Heliospheric Observatory (SOHO), scheduled for launch in November, 1995. This paper has been written to familiarize solar physicists with SUMER and to demonstrate some command procedures for achieving certain scientific observations.

- by michael kuhns
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- Magnetohydrodynamics, Temporal Resolution, Solar Physics, Ultraviolet

Abstract: Major solar flare events have been selected to study the heliographic distribution of solar flares during solar cycle 23. The occurrence of Forbush decreases (FDs), bright solar flares; solar flare index, coronal mass ejections... more

- by Meera Gupta
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- Coronal Mass Ejection, Solar Wind, Solar Magnetic Field, Southern Hemisphere

We are constructing a spectro-Âpolarimeter using the 40-Âcm coronagraph at the Evans Solar Facility of the National Solar Observatory in Sunspot, NM for the purpose of measuring the vector magnetic field in prominences and filaments. The Prominence Magnetometer (ProMag) is comprised of a polarization modulation package and a spectrograph. The modulation optics are located at the prime focus of the coronagraph along with calibration optics and a beamsplitter that creates two beams of orthogonal Stokes states. The spectrograph resides at the coude focus of the coronagraph. The polarizations of the two chromospheric lines of neutral helium, at 587.6 nm and 1083.0 nm, are to be observed simultaneously. We present details of the design of the spectro-Âpolarimeter.

- by A. Lecinski and +2
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- Solar Magnetic Field, Solar Prominences
- by Mathieu Ossendrijver
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- Magnetohydrodynamics, Convection, Dynamo theory, Solar Magnetic Field
- by Karuppanagounder Somasundaram
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- Physics, Magnetohydrodynamics, Solar Physics, Solar Magnetic Field
- by Steven Snowden
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- Geochemistry, Geophysics, Coma, X Rays
- by Ilidio Lopes
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- Solar Magnetic Field, Oscillations, Phase Space
- by D. Grandi
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- Solar Activity, Stochastic Simulation, Solar Wind, Solar Magnetic Field
- by Vasyl Yurchyshyn and +1
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- Mechanical Engineering, Aerospace Engineering, Space, Magnetic field
- by Atanas Atanassov and +2
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- Physics, Solar Activity, Solar Magnetic Field, Quantum Harmonic Oscillator
- by John Beckman
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- Physics, Organic Chemistry, Astrophysical Plasma, Solar Activity
- by Van Der Linden
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- Plasma Physics, Magnetohydrodynamics, Solar Physics, Differential Equations
- by Irina Kitiashvili
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- Physics, Magnetohydrodynamics, Turbulence, Kinetics
- by J. Hoeksema
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- Multidisciplinary, Coronal Mass Ejection, Space Weather, Case Study
- by nandita srivastava
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- X Rays, Coronal Mass Ejection, Space Weather, Solar Energetic Particle Events
- by Roberto Casini
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- Organic Chemistry, Astrophysical Plasma, Magnetic field, Solar Magnetic Field

Recent in situ spacecraft observations and the analysis of the galactic cosmic ray intensity at Earth have shown that the heliospheric magnetic field exhibited a north-south asymmetry and that the heliospheric current sheet was inclined with respect to the solar equator during the years around the last sunspot minimum (1995-1996). In this paper we show that both heliospheric characteristics are due to the particular way the solar magnetic field evolves. The north-south asymmetry can be explained with the evolution of the quadrupolar component of the field in the solar magnetosphere and the inclination of the heliospheric current sheet could be a result of the presence of an inclined relic dipolar field in the Sun, as has been suggested by Bravo and Stewart [1995].

- by Pranaba Nayak
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- Solar Activity, Regression Analysis, Solar Wind, Solar Magnetic Field
- by Donald Boucher
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- Magnetohydrodynamics, Fluid Mechanics, Atmospheric Modeling, Quantum Mechanics
- by E. Romashets
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- Temporal dynamics, Magnetic field, Earth Observation, Coronal Mass Ejection

This chapter is basically divided into 2 parts. In the first part, the important properties of the solar magnetic field are summarized. The discussion begins with a simple introduction to solar magneto hydrodynamics. This introduction will be sufficient to understand the current status of the solar dynamo theory that follows. Some very curious and interesting results on force free fields are then presented in very basic terms. Finally, the application of this theoretical framework to the problems of coronal heating, solar flares and coronal mass ejections are developed in a simple unified scheme, based on a hierarchy of physical conditions. The second part consists of a tutorial on magnetographs. It begins with a description of polarization of light from very fundamental notions of coherence of light. This is followed by simple but comprehensive explanations of the Zeeman and Hanle effects along with the necessary basic ideas of quantum physics of scattering of light. Then the worki...

- by P. Venkatakrishnan
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- Quantum Physics, Solar Magnetic Field, Theoretical Framework