Longitudinally Averaged Magnetic Field

Time-latitude diagram of the longitudinally averaged magnetic field in the solar photosphere for the last three activity cycles. The emergence of magnetic flux in active regions generates the familiar 'butterfly wings' in lower latitudes. The combined effects of differential rotation, convection, and meridional circulation lead to the magnetic flux transport to high latitudes and thus cause the reversals of the polar magnetic fields in phase with the activity cycle (courtesy D....

Sources and Sinks of Ring Current Particles

Source Mechanisms The relative importance of various source mechanisms is not fully understood. Our prior discussion indicates that at least some of the ring current particles are injected from the plasma sheet due to reconnection. For these particle adiabatic heating (betatron effect) is one of the main acceleration mechanisms. For instance a particle starting from 8 Re down-tail doubles it energy by drifting to 6 RE and increases it energy by a factor of 20 when it drifts to L 3. Note that...

The Extraterrestrial Field

As far as effects on humans are concerned only the particle component of the space radiation has to be taken into account. Generally speaking it consists of 85 protons, 14 helium ions (alpha particles) and to about 1 of heavier nuclei, extending as far as nickel. Their relative abundance is shown in Fig. 1, the total fluence rate is about 4cm-2 s-1 at solar minimum (see below). The energies span over a wide range with a maximum of about 107 MeV u. The differential fluence distributions are...

R3

Where BE p0ME 4nREE 3.11 10 5 T is magnetic field at the equator on the Earth's surface. To evaluate magnetic field properties is is helpful to evaluate the magnetic field magnitude and to use an equation to parameterize magnetic field lines r L cos2 A where L is the distance (in rE) at which a field line crosses the equatorial plane (Mcllwain L parameter) and r is measured in Earth radii rE. This parametrization allows for instance to determine the magnetic field magnitude along a specific...

Info

Magnetic Parker Loop

Directly observed 10-year averaged sunspot numbers (group sunspot number since 1611, solid line) and sunspot numbers reconstructed from the 10Be content in an ice core drilled in Antarctica (dot-dashed line) for the time between AD 850 and 1900 (Usoskin et al., 2000 71 ). Various grand minima and the medieval maximum of solar activity are indicated. The figure clearly shows that the average solar activity since about 1940 is roughly twice as large as the overall average since 850....

References

Space Sci., 12, 273, 1964. 2. H. Alfven Tellus, 9, 92-6, 1957. 3. B. J. Anderson, T.-D. Phan, and S. A. Fuselier J. Geophys. Res., 102, 9531, 1997. 4. V. Angelopoulos, W. Baumjohann, C. F. Kennel, F. V. Coronti, M. G. Kivelson, R. Pellat, R. J. Walker, H. Luehr, and G. Paschmann. J. Geophys. Res., 97, 4 27-4 39, April 1992. 5. W. I. Axford and C. O. Hines geomagnetic storms. Can. J. Phys., 39, 1433, 1961. 6. W. B. Baumjohann and R. A. Treumann. Basic Space Plasma Physics...

Single Event Effects

In general terms, a Single Event Effect (SEE) is defined as a radiation induced observable effect in microelectronics circuits caused by a single charged particle losing energy by ionisation in a small sensitive target. Single event effects are instantaneous, and are evaluated as a probability of occurrence within a known mission time, which depends on the energetic particle environment and device characteristics. There are many different types of SEEs with the two main categories of soft...

Displacement Damage

Displacement damage is the main degradation mechanism in space for certain semiconductor devices, such as solar cells, charge-coupled devices, and other photonic devices. Displacement damage is commonly described in terms of Non-Ionising Energy Loss (NIEL), which refers to that part of absorbed energy not going into the ionisation of the medium. NIEL represents the kinetic energy transferred in the interactions of incident particles to the entire atoms of the medium, and typically is orders of...

The Application of Radio Diagnostics to the Study of the Solar Drivers of Space Weather

Density Scale Height Sun Corona

Alexander Warmuth and Gottfried Mann Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany Abstract. The application of radio observations to the study of the solar drivers of space weather - flares and CMEs - is reviewed. The different radio emission mechanisms relevant in the solar corona and in interplanetary space are discussed, with an emphasis on plasma emission. The principal types of instrumentation used are presented, as well as some basic techniques which...

Kqi

Illustration of line conservation Fig. 16. Illustration of line conservation refers to the maximum variance direction and k to the minimum variance direction. It is seen that the minimum variance eigenvector direction of the magnetic field is closely aligned with the maximum variance eigenvector of the electric field. A central problem of magnetospheric dynamics and space weather is the transport of mass momentum, and energy through the magnetopause boundary into the magnetosphere. For...

Particle Precipitation

The particles precipitating from the magnetosphere into the ionosphere during space weather events are mainly electrons with energies of a few keV. They are spiralling around the geomagnetic field lines and interact with neutrals and ions by collisions. Neutrals are ionised by these collisions and the ion production as a function of particle energy and altitude can be described with the relation Fig. 2. Flow chart of space weather effects in the ionosphere and atmosphere. Fig. 2. Flow chart of...

Magnetic Storms

Large solar flares or CME's lead to strong perturbations of the terrestrial magnetosphere for long periods of time (days). Typically the dynamic solar wind pressure is strongly enhanced for many hours leading to a considerable compression of the entire magnetosphere. The effects of a CME can be amplified if in addition the IMF is very large and southward. In this cases it is possible to have several substorms over the course of a magnetic storm. Typically electric fields in the magnetosphere...

Phr

Closed magnetic boundary, there is no plasma flow across the boundary, and the total pressure is balanced p + Bf (2 ,0) _ 0. For the rotational discontinuity the normal magnetic field is nonzero such that the geomagnetic field is connected to the IMF. In the deHoffmann-Teller frame (E _ v x B _ 0 or v B) the velocity normal to the discontinuity satisfies un _ u n with UAn _ Bn p0p. Other important relations for the rotational discontinuity are Btd _ Btu Pd _ Pu and ut _ vAt where the last...

IphVsIa Vsisvs ItVs

When equilibrium has been reached, the satellite surface potential Vs has a value giving the total current It 0. In (1), Ie and Ii are the currents due to incident plasma electrons and ions, respectively. Since the density and kinetic energy of electrons and positively charged ions are approximately the same, and because the mass of the electrons is much smaller than that of the ions, the electrons move much faster, and the negative electron current is greater than the positive ion current. The...

The Magnetosphere

Earth Magnetic Dipole Magnetopause

Geophysical Institute, University Alaska Fairbanks, AK 99775-7320, USA Abstract. First, a brief history of magnetospheric research and a description of the basic structure of the magnetosphere is given. Following are detailed discussions of the major magnetospheric structures, i.e. the bow shock, the magnetosheath, the magnetopause, and the magnetotail. Finally, the role of the inner magnetosphere for geomagnetic storms, which are important mainfestations of space weather, is explained. The...

Conclusion

Solar non-thermal radio radiation is a valuable tool for studying solar activity, in particular with respect to the solar eruptive phenomena (flares and CMEs) that are the main drivers of space weather. Observations at shorter wavelengths (microwaves to meter waves) provide information on the primary energy release and particle acceleration in flares, as well as on the initial development of CMEs and smaller-scale ejecta (i.e. plasmoids) and associated phenomena, such as shock waves. Type III...

Mit

Then the magnetopause is identified as a sudden large change of the magnetic field orientation (and magnitude) in the direction tangential to the boundary. On the Earthward side of the boundary the magnetic field turns predominantly into the northward z direction. At the magnetopause the density may decrease slightly and the plasma consists of a mixture of magnetospheric (energetic) and magnetosheath (cold) particles. At the same time the plasma velocity changes...

Introduction to Space Weather

Laboratory for Atmospheric and Space, University of Colorado, Boulder, CO 80303, USA Abstract. Adverse space weather is one of the principal threats to modern human technology. Solar coronal mass ejections, large solar flares, and high-speed solar wind streams often lead to sequences of damaging disturbances within the Earth's magnetosphere, in the atmosphere, and even on the Earth's surface. Powerful and long-lasting geomagnetic storms can develop following solar disturbances and enhancements...

Year

An example of degradation of the solar array output power (upper panel) and silicon detector leakage current (lower panel) due to displacement damage SOHO ERNE experiment. Four major space weather events are indicated, with inset images from the SOHO LASCO and SOHO EIT. Degradations in solar array power output and increases in detector leakage current are evident coinciding with the solar events, and are most probably due to displacement damage caused by high-energy protons in the...

Contents

Daniel N. 2 Space Weather Effects 3 Energetic Electrons and Space Weather 4 Magnetospheric Substorms 5 Space Weather Effects on the Electric Power System 13 6 Future Directions in Space Weather The Sun and Its Restless Magnetic Field Manfred 2 The Structure of the 3 Solar Magnetic 3.2 Active 3.3 Global Transport of Magnetic Flux 3.4 The Solar Cycle and Its Long-Term 4 Origin of the Magnetic 4.1 Models of the Solar 4.2 Origin of the Long-Term The Application of Radio Diagnostics to the Study of...

Surface Charging

In a comprehensive study of space environment effects on space systems (Koons et al., 1999 67 ), surface charging was found to be the most significant cause of spacecraft anomalies leading to mission failures. Surface charging is the process of electric charge accumulation on surfaces exposed to space environment. It is produced by interactions between satellite surfaces and space plasma, geomagnetic fields, and solar electromagnetic radiation (Leach and Alexander, 1995 68 ). Due to changing...