scholarly journals First results from CSSWE CubeSat: Characteristics of relativistic electrons in the near-Earth environment during the October 2012 magnetic storms

2013 ◽  
Vol 118 (10) ◽  
pp. 6489-6499 ◽  
Author(s):  
X. Li ◽  
Q. Schiller ◽  
L. Blum ◽  
S. Califf ◽  
H. Zhao ◽  
...  
Keyword(s):  
Magnetic Storms ◽  
Relativistic Electrons ◽  
Earth Environment ◽  
First Results

Generation of magnetic and particle Pc5 pulsations during the recovery phase of strong magnetic storms

2010 ◽  
Vol 466 (2123) ◽  
pp. 3363-3390 ◽  
Author(s):  
V. Pilipenko ◽  
O. Kozyreva ◽  
V. Belakhovsky ◽  
M. J. Engebretson ◽  
S. Samsonov
Keyword(s):  
Solar Wind ◽  
Spatial Structure ◽  
Stable State ◽  
Low Frequency ◽  
Solar Wind Plasma ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Relativistic Electrons ◽  
Oscillatory Systems ◽  
Using Data

The dynamics of intense ultra-low-frequency (ULF) activity during three successive strong magnetic storms during 29–31 October 2003 are considered in detail. The spatial structure of Pc5 waves during the recovery phases of these storms is considered not only from the perspective of possible physical mechanisms, but as an important parameter of the ULF driver of relativistic electrons. The global structure of these disturbances is studied using data from a worldwide array of magnetometers and riometers augmented with data from particle detectors and magnetometers on board magnetospheric satellites (GOES, LANL). The local spatial structure is examined using the IMAGE magnetometers and Finnish riometer array. Though a general similarity between the quasi-periodic magnetic and riometer variations is observed, their local propagation patterns turn out to be different. To interpret the observations, we suggest a hypothesis of coupling between two oscillatory systems—a magnetospheric magnetohydrodynamic (MHD) waveguide/resonator and a system consisting of turbulence + electrons. We propose that the observed Pc5 oscillations are the result of MHD waveguide excitation along the dawn and dusk flanks of the magnetosphere. The magnetospheric waveguide turns out to be in a meta-stable state under high solar wind velocities, and quasi-periodic fluctuations of the solar wind plasma density stimulate the waveguide excitation.

scholarly journals Association of radiation belt electron enhancements with earthward penetration of Pc5 ULF waves: a case study of intense 2001 magnetic storms

2015 ◽  
Vol 33 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
M. Georgiou ◽  
I. A. Daglis ◽  
E. Zesta ◽  
G. Balasis ◽  
I. R. Mann ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Recovery Phase ◽  
Wave Activity ◽  
Magnetic Storms ◽  
Ulf Waves ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Magnetometer Arrays ◽  
The One

Abstract. Geospace magnetic storms, driven by the solar wind, are associated with increases or decreases in the fluxes of relativistic electrons in the outer radiation belt. We examine the response of relativistic electrons to four intense magnetic storms, during which the minimum of the Dst index ranged from −105 to −387 nT, and compare these with concurrent observations of ultra-low-frequency (ULF) waves from the trans-Scandinavian IMAGE magnetometer network and stations from multiple magnetometer arrays available through the worldwide SuperMAG collaboration. The latitudinal and global distribution of Pc5 wave power is examined to determine how deep into the magnetosphere these waves penetrate. We then investigate the role of Pc5 wave activity deep in the magnetosphere in enhancements of radiation belt electrons population observed in the recovery phase of the magnetic storms. We show that, during magnetic storms characterized by increased post-storm electron fluxes as compared to their pre-storm values, the earthward shift of peak and inner boundary of the outer electron radiation belt follows the Pc5 wave activity, reaching L shells as low as 3–4. In contrast, the one magnetic storm characterized by irreversible loss of electrons was related to limited Pc5 wave activity that was not intensified at low L shells. These observations demonstrate that enhanced Pc5 ULF wave activity penetrating deep into the magnetosphere during the main and recovery phase of magnetic storms can, for the cases examined, distinguish storms that resulted in increases in relativistic electron fluxes in the outer radiation belts from those that did not.

scholarly journals Relativistic electrons and magnetic storms: 1992-1995

1998 ◽  
Vol 25 (11) ◽  
pp. 1817-1820 ◽  
Author(s):  
Geoffrey D. Reeves
Keyword(s):  
Magnetic Storms ◽  
Relativistic Electrons

Which magnetic storms produce relativistic electrons at geosynchronous orbit?

2001 ◽  
Vol 106 (A8) ◽  
pp. 15533-15544 ◽  
Author(s):  
T. P. O'Brien ◽  
R. L. McPherron ◽  
D. Sornette ◽  
G. D. Reeves ◽  
R. Friedel ◽  
...  
Keyword(s):  
Magnetic Storms ◽  
Geosynchronous Orbit ◽  
Relativistic Electrons

Discussion of the Oblique Rotator Model Cases Of 108 Aqr and x Serp.

1976 ◽  
Vol 32 ◽  
pp. 577-588
Author(s):  
C. Mégessier ◽  
V. Khokhlova ◽  
T. Ryabchikova
Keyword(s):  
Mathematical Formulation ◽  
The Other ◽  
Rotator Model ◽  
Oblique Rotator ◽  
First Results

My talk will be on the oblique rotator model which was first proposed by Stibbs (1950), and since received success and further developments. I shall present two different attempts at describing a star according to this model and the first results obtained in the framework of a Russian-French collaboration in order to test the precision of the two methods. The aim is to give the best possible representation of the element distributions on the Ap stellar surfaces. The first method is the mathematical formulation proposed by Deutsch (1958-1970) and applied by Deutsch (1958) to HD 125248, by Pyper (1969) to α2CVn and by Mégessier (1975) to 108 Aqr. The other one was proposed by Khokhlova (1974) and used by her group.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 250-251
Author(s):  
H. Seiler ◽  
U. Haas ◽  
K.H. Körtje
Keyword(s):  
Bulk Material ◽  
High Vacuum ◽  
Optical Methods ◽  
Metal Particles ◽  
Silver Particles ◽  
Low Loss ◽  
Plasmon Excitation ◽  
First Results ◽  
Diffraction Patterns ◽  
Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

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