Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015

Abstract

Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection‐driven event occurred with a Dst (storm time ring current index) value reaching −223 nT. On 22 June 2015 another strong storm (Dst reaching −204 nT) was recorded. These two storms each produced almost total loss of radiation belt high‐energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong “butterfly” distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported “impenetrable barrier” at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.

New advantages of the combined GPS and GLONASS observations for high-latitude ionospheric irregularities monitoring: case study of June 2015 geomagnetic storm

“…In the present paper, we demonstrate the advantages of the multi-constellation measurements for high-latitude ionospheric irregularities monitoring for the case study of the June 2015 geomagnetic storm. Baker et al (2016) also reported about the sudden loss of energetic particles due to the large solar wind dynamic pressure increase on June 22, 2015, after an arrival of the strong interplanetary shock and the CME passage. The sudden storm commencement was registered at 18:33 UT on June 22, 2015, followed by a SYM-H increase to ~88 nT at 18:37 UT.…”

The Acceleration of Ultrarelativistic Electrons During a Small to Moderate Storm of 21 April 2017

“…Ma et al (2016) also showed that for 3.4 MeV electrons, the local acceleration caused by the chorus waves is the most important mechanism causing significant flux enhancements during the geomagnetic storm on 1 March 2013 Baker et al (2016),. Similarly, Li et al (2014) simulated the dynamics of~500 keV to 5.6 MeV electrons during the intense storm on 17 March 2013 using a 2-D diffusion model.…”

On the Use of Different Magnetic Field Models for Simulating the Dynamics of the Outer Radiation Belt Electrons During the October 1990 Storm

“…Known to be one of the strongest event of the last decades, it has been well recorded by the Van Allen Probes (Baker et al, 2016) as well as the European PROBA-V satellite (Pierrard & Lopez Rosson, 2016) and has already been the topic of numerical simulations (Li et al, 2016). Known to be one of the strongest event of the last decades, it has been well recorded by the Van Allen Probes (Baker et al, 2016) as well as the European PROBA-V satellite (Pierrard & Lopez Rosson, 2016) and has already been the topic of numerical simulations (Li et al, 2016).…”