A Survey on High-energy Protons Response to Geomagnetic Storm in the Inner Radiation Belt

Abstract. RBSPA observations suggest that the inner radiation belt high energy proton fluxes drop significantly during the storm main phase and recover in parallel to as the SYM-H index [Xu et al., 2019]. A natural problem arises: are these storm‐time proton flux variations in response to the magnetic field modifications adiabatic? Based on Liouville's theorem and conservation of the first and third adiabatic invariants, the fully adiabatic effects of high energy protons in the inner radiation belt have been quantitatively evaluated. Two case studies show that theoretically calculated, adiabatic flux decreases are in good agreement with RBSPA observations. Statistical survey of 67 geomagnetic storms which occurred in 2013–2016 has been conducted. The results confirm that the fully adiabatic response constitutes the main contribution 90 % to the changes in high energy protons in inner radiation belt during the storm main and recovery phases. It indicates that adiabatic invariants of the inner belt high energy protons are well preserved for majority of storms. Phase space density results also support adiabatic effect controls the varication of high energy protons especially for small and medium geomagnetic storms. Non-adiabatic effects could play important role for the most intense storms with fast changes in magnetic configuration.

Download Full-text

The dynamics of the inner boundary of the outer radiation belt during geomagnetic storms

10.5194/egusphere-egu2020-19607 ◽

2020 ◽

Author(s):

Xiaofei Shi ◽

Jie Ren ◽

Qiugang Zong

Keyword(s):

Radiation Belt ◽

Electron Flux ◽

Geomagnetic Storms ◽

Minimum Energy ◽

Onset Time ◽

Recovery Phase ◽

Outer Radiation Belt ◽

H Index ◽

Late Recovery ◽

Energy Dependent

We present a statistical study of energy-dependent and L shell-dependent inner boundary of the outer radiation belt during 37 isolated geomagnetic storms using observations from Van Allen Probes from 2013 to 2017. There are mutual transformations between "V-shaped" and "S-shaped" inner boundaries during different storm phases, resulting from the competition among electron loss, radial transport and local acceleration. The radial position, onset time, Est (the minimum energy at Lst where the inner boundary starts to exhibit an S-shaped form), and the radial width of S-shaped boundary (&#916;L) are quantitatively defined according to the formation of a reversed energy spectrum (electron flux going up with increasing energies from hundreds of keV to ~1 MeV) from a kappa-like spectrum (electron flux steeply falling with increasing energies). The case and statistical results present that (1) The inner boundary has repeatable features associated with storms: the inner boundary is transformed from S-shaped to V-shaped form in several hours during the storm commencement and main phase, and retains in the V-shaped form for several days until it evolves into S-shaped during late recovery phase; (2) &#916;L shows positive correlation with SYM-H index; (3) The duration of the V-shaped form is positively correlated with the storm intensity and the duration of the recovery phase; (4) The minimum energy Est are mainly distributed in the range of 100-550 keV. All these findings have important implications for understanding the dynamics of energetic electrons in the slot region and the outer radiation belt during geomagnetic storms.

Download Full-text

Observation of High-Energy Particles in the Inner Radiation Belt by the HEP Instrument of the Arase Satellite

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES AEROSPACE TECHNOLOGY JAPAN ◽

10.2322/tastj.18.398 ◽

2020 ◽

Vol 18 (6) ◽

pp. 398-403

Author(s):

Honoka TODA ◽

Wataru MIYAKE ◽

Takefumi MITANI ◽

Takeshi TAKASHIMA ◽

Yoshizumi MIYOSHI ◽

...

Keyword(s):

Radiation Belt ◽

High Energy ◽

High Energy Particles

Download Full-text

Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation

Annales Geophysicae ◽

10.1007/s00585-996-0608-3 ◽

1996 ◽

Vol 14 (6) ◽

pp. 608-618 ◽

Cited By ~ 189

Author(s):

T. Iyemori ◽

D. R. K. Rao

Keyword(s):

Ring Current ◽

Geomagnetic Storms ◽

Sharp Decrease ◽

Geomagnetic Disturbance ◽

Substorm Onset ◽

Significant Development ◽

H Index ◽

Magnetospheric Tail ◽

Storms And Substorms ◽

Substorm Onsets

Abstract. In order to investigate the causal relationship between magnetic storms and substorms, variations of the mid-latitude geomagnetic indices, ASY (asymmetric part) and SYM (symmetric part), at substorm onsets are examined. Substorm onsets are defined by three different phenomena; (1) a rapid increase in the mid-latitude asymmetric-disturbance indices, ASY-D and ASY-H, with a shape of so-called `mid-latitude positive bay\\'; (2) a sharp decrease in the AL index; (3) an onset of Pi2 geomagnetic pulsation. The positive bays are selected using eye inspection and a pattern-matching technique. The 1-min-resolution SYM-H index, which is essentially the same as the hourly Dst index except in terms of the time resolution, does not show any statistically significant development after the onset of substorms; it tends to decay after the onset rather than to develop. It is suggested by a simple model calculation that the decay of the magnetospheric tail current after substorm onset is responsible for the decay of the Dst field. The relation between the IMF southward turning and the development of the Dst field is re-examined. The results support the idea that the geomagnetic storms and substorms are independent processes; that is, the ring-current development is not the result of the frequent occurrence of substorms, but that of enhanced convection caused by the large southward IMF. A substorm is the process of energy dissipation in the magnetosphere, and its contribution to the storm-time ring-current formation seems to be negligible. The decay of the Dst field after a substorm onset is explained by a magnetospheric energy theorem.

Download Full-text

ULF Wave Power During Geomagnetic Storms and Implications for Radial Diffusion Processes

10.5194/egusphere-egu21-11203 ◽

2021 ◽

Author(s):

Jasmine Sandhu ◽

Jonathan Rae ◽

John Wygant ◽

Aaron Breneman ◽

Sheng Tian ◽

...

Keyword(s):

Statistical Analysis ◽

Diffusion Coefficients ◽

Radiation Belt ◽

Geomagnetic Storms ◽

Radial Diffusion ◽

Ulf Waves ◽

Wave Power ◽

Outer Radiation Belt ◽

Large Variability ◽

Ulf Wave

Ultra Low Frequency (ULF) waves drive radial diffusion of radiation belt electrons, where this process contributes to and, at times, dominates energisation, loss, and large scale transport of the outer radiation belt. In this study we quantify the changes and variability in ULF wave power during geomagnetic storms, through a statistical analysis of Van Allen Probes data for the time period spanning 2012 &#8211; 2019. The results show that global wave power enhancements occur during the main phase, and continue into the recovery phase of storms. Local time asymmetries show sources of ULF wave power are both external solar wind driving as well as internal sources from coupling with ring current ions and substorms.The statistical analysis demonstrates that storm time ULF waves are able to access lower L values compared to pre-storm conditions, with enhancements observed within L = 4. We assess how magnetospheric compressions and cold plasma distributions shape how ULF wave power propagates through the magnetosphere. Results show that the Earthward displacement of the magnetopause is a key factor in the low L enhancements. Furthermore, the presence of plasmaspheric plumes during geomagnetic storms plays a crucial role in trapping ULF wave power, and contributes significantly to large storm time enhancements in ULF wave power.The results have clear implications for enhanced radial diffusion of the outer radiation belt during geomagnetic storms. Estimates of storm time radial diffusion coefficients are derived from the ULF wave power observations, and compared to existing empirical models of radial diffusion coefficients. We show that current Kp-parameterised models, such as the Ozeke et al. [2014] model, do not fully capture the large variability in storm time radial diffusion coefficients or the extent of enhancements in the magnetic field diffusion coefficients.

Download Full-text

On the effect of ULF waves on the outer radiation belt during geomagnetic storms

10.5194/egusphere-egu21-5977 ◽

2021 ◽

Author(s):

Christopher Lara ◽

Pablo S. Moya ◽

Victor Pinto ◽

Javier Silva ◽

Beatriz Zenteno

Keyword(s):

Relativistic Electron ◽

Radiation Belt ◽

Geomagnetic Storms ◽

Cumulative Effect ◽

Radiation Belts ◽

Ulf Waves ◽

Relativistic Electrons ◽

Relative Role ◽

Outer Radiation Belt ◽

Ulf Wave

The inner magnetosphere is a very important region to study, as with satellite-based communications increasing day after day, possible disruptions are especially relevant due to the possible consequences in our daily life. It is becoming very important to know how the radiation belts behave, especially during strong geomagnetic activity. The radiation belts response to geomagnetic storms and solar wind conditions is still not fully understood, as relativistic electron fluxes in the outer radiation belt can be depleted, enhanced or not affected following intense activity. Different studies show how these results vary in the face of different events. As one of the main mechanisms affecting the dynamics of the radiation belt are wave-particle interactions between relativistic electrons and ULF waves. In this work we perform a statistical study of the relationship between ULF wave power and relativistic electron fluxes in the outer radiation belt during several geomagnetic storms, by using magnetic field and particle fluxes data measured by the Van Allen Probes between 2012 and 2017. We evaluate the correlation between the changes in flux and the cumulative effect of ULF wave activity during the main and recovery phases of the storms for different position in the outer radiation belt and energy channels. Our results show that there is a good correlation between the presence of ULF waves and the changes in flux during the recovery phase of the storm and that correlations vary as a function of energy. Also, we can see in detail how the ULF power change for the electron flux at different L-shell We expect these results to be relevant for the understanding of the relative role of ULF waves in the enhancements and depletions of energetic electrons in the radiation belts for condition described.

Download Full-text

Adhesion Force Between High Energy Surfaces in Vapor Atmosphere

MRS Proceedings ◽

10.1557/proc-366-33 ◽

1994 ◽

Vol 366 ◽

Cited By ~ 4

Author(s):

Jerome Crassous ◽

Jean-Luc Loubet ◽

Elisabeth Charlaix

Keyword(s):

Liquid Bridge ◽

Adhesion Force ◽

Van Der Waals ◽

Surface Force ◽

High Energy ◽

Attractive Force ◽

Experimental Measurements ◽

Metallic Substrates ◽

Energy Surfaces ◽

Good Agreement

ABSTRACTWe report experimental measurements of the adhesion force between metallic substrates in undersaturated heptane vapor atmosphere, with a surface force apparatus. The attractive force between the substrates is strongly dependant of the condensation of a liquid bridge connecting the surfaces. The results show the importance of wetting phenomena for the maximum attractive force: we find that this maximum attraction varies as the power two-third of the curvature of the meniscus connecting the surfaces, in good agreement with the theory of Van der Waals wetting.

Download Full-text

Variability of the pitch angle distribution of radiation belt ultrarelativistic electrons during and following intense geomagnetic storms: Van Allen Probes observations

Journal of Geophysical Research Space Physics ◽

10.1002/2015ja021065 ◽

2015 ◽

Vol 120 (6) ◽

pp. 4863-4876 ◽

Cited By ~ 24

Author(s):

Binbin Ni ◽

Zhengyang Zou ◽

Xudong Gu ◽

Chen Zhou ◽

Richard M. Thorne ◽

...

Keyword(s):

Pitch Angle ◽

Radiation Belt ◽

Geomagnetic Storms ◽

Angle Distribution ◽

Pitch Angle Distribution ◽

Van Allen Probes

Download Full-text

RELATIONSHIP OF THE ASY-H INDEX WITH INTERPLANETARY MEDIUM PARAMETERS AND AURORAL ACTIVITY IN MAGNETIC STORM MAIN PHASES DURING CIR AND ICME EVENTS

Solnechno-Zemnaya Fizika ◽

10.12737/szf-61202004 ◽

2020 ◽

Vol 6 (1) ◽

pp. 43-50

Author(s):

Roman Boroev ◽

Mikhail Vasiliev

Keyword(s):

Magnetic Storm ◽

Interplanetary Medium ◽

Magnetic Storms ◽

Main Phase ◽

Storm Main Phase ◽

H Index ◽

Auroral Activity ◽

Different Types ◽

Relationship Of ◽

The Relationship

In this study, we examine the relationship of the ASY-H index characterizing the partial ring current intensity with interplanetary medium parameters and auroral activity during the main phase of magnetic storms, induced by the solar wind (SW) of different types. Over the period 1979–2017, 107 magnetic storms driven by CIR and ICME (MC + Ejecta) events have been selected. We consider magnetic storms with Dstmin≤ – 50 nT. The average ASY-H index (ASYaver) during the magnetic storm main phase is shown to increase with increasing SW electric field and southward IMF Bz regardless of SW type. There is no relationship between ASYaver and SW velocity. For the CIR and ICME events, the average AE (AEaver) and Kp (Kp aver) indices have been found to correlate with ASYaver. The highest correlation coefficient between AEaver and ASYaver (r = 0.74) is observed for the magnetic storms generated by CIR events. A closer relationship between Kp aver and ASYaver (r = 0.64) is observed for the magnetic storms induced by ICME events. The ASYaver variations correlate with Dstmin. The relationship between ASYaver and the rate of storm development is weak.

Download Full-text

Flight Demonstration of a 2-Micron, Double Plused CO2 IPDA Lidar Instrument

EPJ Web of Conferences ◽

10.1051/epjconf/202023703013 ◽

2020 ◽

Vol 237 ◽

pp. 03013

Author(s):

Jirong Yu ◽

Mulugeta Petros ◽

Upendra Singh ◽

Tamer Refaat ◽

Karl Reithmaier ◽

...

Keyword(s):

Column Density ◽

High Energy ◽

Density Difference ◽

Lidar Measurement ◽

Differential Absorption ◽

Air Samples ◽

Lidar Measurements ◽

Langley Research Center ◽

Good Agreement

NASA Langley Research Center (LaRC) developed a double pulsed, high energy 2-micron Integrated Path Differential Absorption (IPDA) lidar instrument to measure atmospheric CO2 column density. The 2-μm double pulsed IPDA lidar was flown ten times in March and April of 2014. It was determined that the IPDA lidar measurement is in good agreement with an in-situ CO2 measurement by a collocated NOAA flight. The average column CO2 density difference between the IPDA lidar measurements and the NOAA air samples is 1.48ppm in the flight altitudes of 3 to 6.1 km.

Download Full-text