scholarly journals Auroral particles associated with a substorm brightening arc

2005 ◽  
Vol 32 (6) ◽  
Author(s):  
K. Yago
Keyword(s):  
Auroral Particles

scholarly journals Characteristics of auroral particles observed by EXOS-C.

1985 ◽  
Vol 37 (3) ◽  
pp. 347-363 ◽  
Author(s):  
Nobuyuki KAYA ◽  
Toshifumi MUKAI ◽  
Haruya MATSUMOTO ◽  
Tomizo ITOH
Keyword(s):  
Auroral Particles

scholarly journals The correlation of solar radio bursts by magnetic activity and cosmic rays

1959 ◽  
Vol 9 ◽  
pp. 210-213
Author(s):  
A. R. Thompson
Keyword(s):  
Cosmic Rays ◽  
Radio Astronomy ◽  
Solar Radio ◽  
Magnetic Activity ◽  
Radio Bursts ◽  
Type Ii ◽  
Frequency Range ◽  
Sweep Frequency ◽  
Solar Radio Bursts ◽  
Auroral Particles

The sweep-frequency equipment at the Harvard Radio Astronomy Station, Fort Davis, Texas, has now been running continuously since 1956 September, recording solar radio activity in the frequency range from 100 to 580 Mc/s. The following contribution describes preliminary investigations of the correlation of the radio data with solar corpuscular emissions. This work was initiated to examine the well-known suggestions that the origins of the type II and type III radio bursts are associated with the ejection of auroral particles and cosmic rays respectively.

scholarly journals Global auroral conductance distribution due to electron and proton precipitation from IMAGE-FUV observations

2004 ◽  
Vol 22 (5) ◽  
pp. 1595-1611 ◽  
Author(s):  
V. Coumans ◽  
J.-C. Gérard ◽  
B. Hubert ◽  
M. Meurant ◽  
S. B. Mende
Keyword(s):  
Imaging System ◽  
Potential Drop ◽  
Large Error ◽  
Feedback Mechanism ◽  
Activity Levels ◽  
Auroral Region ◽  
Ionospheric Conductivity ◽  
The North ◽  
Proton Precipitation ◽  
Auroral Particles

Abstract. The Far Ultraviolet (FUV) imaging system on board the IMAGE satellite provides a global view of the north auroral region in three spectral channels, including the SI12 camera sensitive to Doppler shifted Lyman-α emission. FUV images are used to produce instantaneous maps of electron mean energy and energy fluxes for precipitated protons and electrons. We describe a method to calculate ionospheric Hall and Pedersen conductivities induced by auroral proton and electron ionization based on a model of interaction of auroral particles with the atmosphere. Different assumptions on the energy spectral distribution for electrons and protons are compared. Global maps of ionospheric conductances due to instantaneous observation of precipitating protons are calculated. The contribution of auroral protons in the total conductance induced by both types of auroral particles is also evaluated and the importance of proton precipitation is evaluated. This method is well adapted to analyze the time evolution of ionospheric conductances due to precipitating particles over the auroral region or in particular sectors. Results are illustrated with conductance maps of the north polar region obtained during four periods with different activity levels. It is found that the proton contribution to conductance is relatively higher during quiet periods than during substorms. The proton contribution is higher in the period before the onset and strongly decreases during the expansion phase of substorms. During a substorm which occurred on 28 April 2001, a region of strong proton precipitation is observed with SI12 around 14:00MLT at ~75° MLAT. Calculation of conductances in this sector shows that neglecting the protons contribution would produce a large error. We discuss possible effects of the proton precipitation on electron precipitation in auroral arcs. The increase in the ionospheric conductivity, induced by a former proton precipitation can reduce the potential drop along field lines in the upward field-aligned currents by creating an opposite polarization electric field. This feedback mechanism possibly reduces the electron acceleration. Key words. Ionosphere (auroral ionosphere; ionospheremagnetosphere interactions; particle precipitation)

scholarly journals High-resolution maps of the characteristic energy of precipitating auroral particles

2001 ◽  
Vol 106 (A12) ◽  
pp. 28925-28937 ◽  
Author(s):  
M. J. Kosch ◽  
F. Honary ◽  
C. F. del Pozo ◽  
S. R. Marple ◽  
T. Hagfors
Keyword(s):  
High Resolution ◽  
Characteristic Energy ◽  
Auroral Particles

scholarly journals Magnetospheric Processes Possibly Related to the Origin of Cosmic Rays

1981 ◽  
Vol 94 ◽  
pp. 373-391
Author(s):  
Gerhard Haerendel
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Small Scale ◽  
Shear Stresses ◽  
Acceleration Process ◽  
Dayside Magnetopause ◽  
Field Lines ◽  
The Magnetic Field ◽  
Auroral Particles

Two processes are discussed which violate the frozen-in condition in a highly conducting plasma, reconnection and the auroral acceleration process. The first applies to situations in which . It plays an important role in the interaction of the solar wind with the Earth's magnetic field and controls energy input into as well as energetic particle release from the magnetosphere. Detailed in situ studies of the process on the dayside magnetopause reveal its transient and small-scale nature. The auroral acceleration process occurs in the low magnetosphere (β « 1) and accompanies sudden releases of magnetic shear stresses which exist in large-scale magnetospheric-ionospheric current circuits. The process is interpreted as a kind of breaking. The movements of the magnetospheric plasma which lead to a relief of the magnetic tensions occur in thin sheets and are decoupled along the magnetic field lines by parallel electric potential drops. It is this voltage that accelerates the primary auroral particles. The visible arcs are then traces of the magnetic breaking process at several 1000 km altitude.

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