scholarly journals Radiation Belt Response to Fast Reverse Shock at Geosynchronous Orbit

2021 ◽  
Vol 910 (2) ◽  
pp. 154
Author(s):  
Ankush Bhaskar ◽  
David Sibeck ◽  
Shrikanth G. Kanekal ◽  
Howard J. Singer ◽  
Geoffrey Reeves ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Geosynchronous Orbit ◽  
Reverse Shock

scholarly journals LANL* V2.0: global modeling and validation

2011 ◽  
Vol 4 (1) ◽  
pp. 575-594
Author(s):  
J. Koller ◽  
S. Zaharia
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Space Weather ◽  
Radiation Belt ◽  
Geosynchronous Orbit ◽  
Data Sets ◽  
Magnetic Field Model ◽  
Integration Techniques ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Abstract. We describe in this paper the new version of LANL*. Just like the previous version, this new version V2.0 of LANL* is an artificial neural network (ANN) for calculating the magnetic drift invariant, L*, that is used for modeling radiation belt dynamics and for other space weather applications. We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for any type of orbit. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al. (2003). We have validated the model and compared our results to L* calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit. We find that the neural network performs very well for all these orbits with an error typically Δ L* < 0.2 which corresponds to an error of 3% at geosynchronous orbit. This new LANL-V2.0 artificial neural network is orders of magnitudes faster than traditional numerical field line integration techniques with the TS05 model. It has applications to real-time radiation belt forecasting, analysis of data sets involving decades of satellite of observations, and other problems in space weather.

scholarly journals LANL<sup>*</sup>V2.0: global modeling and validation

2011 ◽  
Vol 4 (3) ◽  
pp. 669-675 ◽  
Author(s):  
J. Koller ◽  
S. Zaharia
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Space Weather ◽  
Radiation Belt ◽  
Geosynchronous Orbit ◽  
Data Sets ◽  
Magnetic Field Model ◽  
Integration Techniques ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Abstract. We describe in this paper the new version of LANL*, an artificial neural network (ANN) for calculating the magnetic drift invariant L*. This quantity is used for modeling radiation belt dynamics and for space weather applications. We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for a much larger region. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al. (2003). We have validated the model and compared our results to L* calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit. We find that the neural network performs very well for all these orbits with an error typically ΔL* < 0.2 which corresponds to an error of 3 % at geosynchronous orbit. This new LANL* V2.0 artificial neural network is orders of magnitudes faster than traditional numerical field line integration techniques with the TS05 model. It has applications to real-time radiation belt forecasting, analysis of data sets involving decades of satellite of observations, and other problems in space weather.

scholarly journals Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit

2008 ◽  
Vol 26 (6) ◽  
pp. 1335-1339 ◽  
Author(s):  
R. Kataoka ◽  
Y. Miyoshi
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Radiation Belt ◽  
Dynamic Pressure ◽  
Recovery Phase ◽  
Geosynchronous Orbit ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Flux Enhancement ◽  
Solar Wind Structure

Abstract. We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO). It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa) during rapid speed decrease from very high (>650 km/s) to typical (400–500 km/s) in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.

High-speed stream driven inferences of global wave distributions at geosynchronous orbit: relevance to radiation-belt dynamics

2010 ◽  
Vol 466 (2123) ◽  
pp. 3351-3362 ◽  
Author(s):  
Elizabeth A. MacDonald ◽  
Lauren W. Blum ◽  
S. Peter Gary ◽  
Michelle F. Thomsen ◽  
Michael H. Denton
Keyword(s):  
High Speed ◽  
Radiation Belt ◽  
Recovery Phase ◽  
Wave Activity ◽  
Geosynchronous Orbit ◽  
Relativistic Electrons ◽  
Particle Interactions ◽  
Early Recovery ◽  
Emic Wave ◽  
Major Loss

Three superposed epoch analyses of plasma data from geosynchronous orbit are compared to infer relative distributions of electromagnetic ion cyclotron (EMIC)- and whistler-mode wave instabilities. Both local-time and storm-time behaviours are studied with respect to dynamics of relativistic electrons. Using LANL-GEO particle data and a quasi-linear approximation for the wave growth allows us to estimate the instability of the two wave modes. This simple technique can allow powerful insights into wave–particle interactions at geosynchronous orbit. Whistler-wave activity peaks on the dayside during the early recovery phase and can continue to be above normal levels for several days. The main phase of all storms exhibits the most EMIC-wave activity, whereas in the recovery phase of the most radiation-belt-effective storms, a significantly suppressed level of EMIC activity is inferred. These key results indicate new dynamics relating to plasma delivery, source and response, but support generally accepted views of whistlers as a source process and EMIC-mode waves as a major loss contributor at geosynchronous orbit.

Sign in / Sign up

Export Citation Format

Share Document