OUP accepted manuscript

Raghav, Anil; Choraghe, Komal; Shaikh, Zubair

doi:10.1093/mnras/stz1608

Cited by 11 publications

(5 citation statements)

References 32 publications

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“…ICMEs occasionally interact with the terrestrial magnetic field with sufficient mass, velocity, and southward interplanetary magnetic field (IMF) to cause geomagnetic storms and equatorward extensions of the auroral oval (Gonzalez et al, 1994;Yokoyama et al, 1998;Daglis et al, 1999;Pulkkinen, 2007). Analyses of such solar and geomagnetic storms are more than just of academic interest due to their potential to create space weather conditions that frequently enhance electric currents in space, which in turn can affect essential societal infrastructure such as power grid systems, satellite operations, and long-range communication systems (Pulkkinen, 2007;Baker et al, 2008;Schrijver, 2015;Pulkkinen et al, 2017;Riley et al, 2018;Raghav et al, 2018Raghav et al, , 2019Oliveira et al, 2020aOliveira et al, , 2021aHapgood et al, 2021).…”

mentioning

confidence: 99%

The extreme solar and geomagnetic storms on 1940 March 20–25

Hayakawa

Oliveira

Shea³

et al. 2021

Monthly Notices of the Royal Astronomical Society

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In late March 1940, at least five significant solar flares were reported. They likely launched interplanetary coronal mass ejections (ICMEs), and were associated with one of the largest storm sudden commencements (SSCs) since the year 1868, resulting in space weather hazards that today would have significant societal impacts. The initial solar activity is associated with a short geomagnetic storm and a notable SSC. Afterward, the third flare was reported in the eastern solar quadrant (N12 E37-38) at 11:30–12:30 UT on 23 March, with significant magnetic crochets (up to ≈ |80| nT at Eskdalemuir) during 11:07–11:40 UT. On their basis, we estimate the required energy flux of the source flare as X35±1 in soft X-ray class. The resultant ICMEs caused enormous SSCs (up to > 425 nT recorded at Tucson) and allowed us to estimate an extremely inward magnetopause position (estimated magnetopause standoff position ≈ 3.4 RE). The time series of the resultant geomagnetic storm is reconstructed using a Dst estimate, which peaked at 20 UT on 24 March at ≈ −389 nT. Around the storm main phase, the equatorial boundary of the auroral oval extended ≤ 46.3° at invariant latitudes. This sequence also caused a solar proton event and Forbush decrease (≈ 3%). These sequences indicate pileups of multiple ICMEs, which even achieved a record value of inward magnetopause position. Our analyses of this historical pioneer event bring more insights into possible serious space weather hazards and provide a quantitative basis for future analyses and predictions.

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mentioning

confidence: 99%

The extreme solar and geomagnetic storms on 1940 March 20–25

Hayakawa

Oliveira

Shea³

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…The magnetic and kinetic forces within ICMEs are no longer in perfect equilibrium, leading to the excitation of both MHD and kinetic-scale waves (Jacques 1977). While previous studies have delved into MHD-scale waves within magnetic clouds (Raghav & Kule 2018a, 2018bRaghav et al 2018Raghav et al , 2019Raghav et al , 2023aDhamane et al 2023bDhamane et al , 2024, the understanding of kinetic-scale mode waves remains a challenge. In a recent study, Dhamane et al (2023a) observed one aspect of kineticscale waves, specifically those aligned with the background magnetic field, by studying Alfvén ion cyclotron waves.…”

Section: Resultsmentioning

confidence: 99%

Observation of Kinetic Alfvén Waves inside an Interplanetary Coronal Mass Ejection Magnetic Cloud at 1 au

Kumbhar,

Raghav,

Dhamane

et al. 2024

ApJ

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Recent advancements have significantly enhanced our grasp of interplanetary coronal mass ejections (ICMEs) in the heliosphere. These observations have uncovered complex kinematics and structural deformations in ICMEs, hinting at the possible generation of magnetohydrodynamic (MHD) and kinetic-scale waves. While MHD-scale waves in magnetic clouds have been explored, understanding the dynamics of kinetic-scale mode waves remains challenging. This article demonstrates the first in situ observation of kinetic Alfvén waves (KAWs) within an ICME’s magnetic cloud, notably near the heliospheric current sheet–ICME interaction region, close to the reconnection exhaust. Analysis indicates a distinctive negative bump in the estimated normalized magnetic helicity (σ m = −0.38) around the gyrofrequency spread, indicating a right-handed polarization of the wave. Furthermore, examination across flow angle (θ VB) within the frequency domain reveals a specific zone (90°–135°) showcasing negative helicity fluctuations, confirming the presence of KAWs. Moreover, we noted a significant rise in temperature anisotropy in the vicinity, indicating the role of KAWs in plasma heating. Identifying KAW challenges established notions about ordered magnetic clouds and raises questions about energy transfer processes within these structures. This finding opens the door to a deeper understanding of energy transfer mechanisms within traditionally nondissipative regions and invites further exploration of low-beta plasma heating and the interactions between waves and particles in magnetic clouds.

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“…Recently, we found their existence during CME-CME and CME-HSS interactions, and inside the ICME sheath regions (Raghav & Kule 2018a, 2018bDhamane et al 2022;Raghav et al 2022). Moreover, AWs play a key role in modulating the recovery phase of geomagnetic storms and slowing down the restoration of the magnetosphere toward its pre-storm equilibrium state (Raghav et al 2018(Raghav et al , 2019Shaikh et al 2019b;Choraghe et al 2021;Telloni et al 2021).…”

Section: Introductionmentioning

confidence: 98%

First Analysis of In Situ Observation of Surface Alfvén Waves in an ICME Flux Rope

Raghav

Omkar

Shaikh

et al. 2023

ApJ

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Alfvén waves (AWs) are ubiquitous in space and astrophysical plasma. Their crucial role in various physical processes has triggered intense research in solar–terrestrial physics. Simulation studies have proposed the generation of AWs along the surface of a cylindrical flux rope, referred to as surface AWs (SAWs); however, the observational verification of this distinct wave has been elusive to date. We report the first in situ observation of SAWs in a flux rope of an interplanetary coronal mass ejection. We apply the Walén test to identify them. We have used Elsässer variables to estimate the characteristics of SAWs. They may be excited by the movement of the flux rope’s footpoints or by instabilities along the boundaries of the plasma magnetic cloud. Here, the change in plasma density or field strength in the surface-aligned magnetic field may trigger SAWs.

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OUP accepted manuscript

Cited by 11 publications

References 32 publications

The extreme solar and geomagnetic storms on 1940 March 20–25

The extreme solar and geomagnetic storms on 1940 March 20–25

Observation of Kinetic Alfvén Waves inside an Interplanetary Coronal Mass Ejection Magnetic Cloud at 1 au

First Analysis of In Situ Observation of Surface Alfvén Waves in an ICME Flux Rope

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