Ultra-relativistic Electron Acceleration during High-intensity Long-duration Continuous Auroral Electrojet Activity Events

Hajra, Rajkumar; Tsurutani, Bruce T.; Lu, Quanming; Lakhina, Gurbax S.; Du, Aimin; Echer, Ezequiel; Franco, Adriane M. S.; Bolzan, Mauricio J. A.; Gao, Xinliang

doi:10.3847/1538-4357/ad2dfe

Cited by 2 publications

(1 citation statement)

References 108 publications

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“…It has been noted that relativistic magnetospheric electrons are detected predominately during this phase of the solar cycle (Baker et al, 1990;Li et al, 2001). Hajra et al (2015Hajra et al ( , 2024 have indicated that the acceleration of these relativistic electrons are associated with chorus (Horne et al, 2005;Thorne et al, 2013) during HILDCAA events. Allen et al (1989) showed that the magnetopause moved inside geostationary orbit (L = 6.6) during 13 and 14 March using GOES 7 and GOES 6 magnetic field observations.…”

Section: Geomagnetic Storms and Substormsmentioning

confidence: 99%

Review of the August 1972 and March 1989 (Allen) Space Weather Events: Can We Learn Anything New From Them?

Tsurutani,

Sen,

Hajra

et al. 2024

JGR Space Physics

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Updated summaries of the August 1972 and March 1989 space weather events have been constructed. The features of these two events are compared to the Carrington 1859 event and a few other major space weather events. It is concluded that solar active regions release energy in a variety of forms (X‐rays, EUV photons, visible light, coronal mass ejection (CME) plasmas and fields) and they in turn can produce other energetic effects (solar energetic particles (SEPs), magnetic storms) in a variety of ways. It is clear that there is no strong one‐to‐one relationship between these various energy sinks. The energy is often distributed differently from one space weather event to the next. Concerning SEPs accelerated at interplanetary CME (ICME) shocks, it is concluded that the Fermi mechanism associated with quasi‐parallel shocks is relatively weak and that the gradient drift mechanism (electric fields) at quasi‐perpendicular shocks will produce harder spectra and higher fluxes. If the 4 August 1972 intrinsic magnetic cloud condition (southward interplanetary magnetic field instead of northward) and the interplanetary Sun to 1 au conditions were different, a 4 August 1972 magnetic storm and magnetospheric dawn‐to‐dusk electric fields substantially larger than the Carrington event would have occurred. Under these special interplanetary conditions, a Miyake et al. (2012), https://doi.org/10.1038/nature11123‐like extreme SEP event may have been formed. The long duration complex 1989 storm was probably greater than the Carrington storm in the sense that the total ring current particle energy was larger.

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Section: Geomagnetic Storms and Substormsmentioning

confidence: 99%

Review of the August 1972 and March 1989 (Allen) Space Weather Events: Can We Learn Anything New From Them?

Tsurutani,

Sen,

Hajra

et al. 2024

JGR Space Physics

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Interplanetary Causes and Impacts of the 2024 May Superstorm on the Geosphere: An Overview

Hajra,

Tsurutani,

Lakhina

et al. 2024

ApJ

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The recent superstorm of 2024 May 10–11 is the second largest geomagnetic storm in the space age and the only one that has simultaneous interplanetary data (there were no interplanetary data for the 1989 March storm). The May superstorm was characterized by a sudden impulse (SI+) amplitude of +88 nT, followed by a three-step storm main-phase development, which had a total duration of ∼9 hr. The cause of the first storm main phase with a peak SYM-H intensity of −183 nT was a fast-forward interplanetary shock (magnetosonic Mach number M ms ∼ 7.2) and an interplanetary sheath with a southward interplanetary magnetic field component B s of ∼40 nT. The cause of the second storm's main phase with an SYM-H intensity of −354 nT was a deepening of the sheath B s to ∼43 nT. A magnetosonic wave (M ms ∼ 0.6) compressed the sheath to a high magnetic field strength of ∼71 nT. Intensified B s of ∼48 nT were the cause of the third and most intense storm main phase, with an SYM-H intensity of −518 nT. Three magnetic cloud events with B s fields of ∼25–40 nT occurred in the storm recovery phase, lengthening the recovery to ∼2.8 days. At geosynchronous orbit, ∼76 keV to ∼1.5 MeV electrons exhibited ∼1–3 orders of magnitude flux decreases following the shock/sheath impingement onto the magnetosphere. The cosmic-ray decreases at Dome C, Antarctica (effective vertical cutoff rigidity <0.01 GV) and Oulu, Finland (rigidity ∼0.8 GV) were ∼17% and ∼11%, respectively, relative to quiet-time values. Strong ionospheric current flows resulted in extreme geomagnetically induced currents of ∼30–40 A in the subauroral region. The storm period is characterized by strong polar-region field-aligned currents, with ∼10 times intensification during the main phase and equatorward expansion down to ∼50° geomagnetic (altitude-adjusted) latitude.

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Ultra-relativistic Electron Acceleration during High-intensity Long-duration Continuous Auroral Electrojet Activity Events

Cited by 2 publications

References 108 publications

Review of the August 1972 and March 1989 (Allen) Space Weather Events: Can We Learn Anything New From Them?

Review of the August 1972 and March 1989 (Allen) Space Weather Events: Can We Learn Anything New From Them?

Interplanetary Causes and Impacts of the 2024 May Superstorm on the Geosphere: An Overview

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