Multispacecraft observations of the terrestrial bow shock and magnetopause during extreme solar wind disturbances

Tátrallyay, M.; Erdö́s, G.; Németh, Zoltán; Веригин, М. И.; Vennerstrøm, S.

doi:10.5194/angeo-30-1675-2012

Cited by 9 publications

(4 citation statements)

References 48 publications

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“…(2015) include all IMF components,

{p}_{\mathrm{dyn}}

and the dipole tilt as parameters to give an even better forecasting accuracy under normal solar wind conditions. Nevertheless, most models fail to predict magnetopause locations under extreme pressure conditions (e.g., Suvorova & Dmitriev, 2015; Tátrallyay et al., 2012). In these cases, other parameters can become more significant.…”

Section: Introductionmentioning

confidence: 99%

Study of Extreme Magnetopause Distortions Under Varying Solar Wind Conditions

et al. 2023

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To first order, the magnetopause (MP) is defined by a pressure balance between the solar wind and the magnetosphere. The boundary moves under the influence of varying solar wind conditions and transient foreshock phenomena, reaching unusually large and small distances from the Earth. We investigate under which solar wind conditions such extreme MP distortions occur. Therefore, we construct a database of magnetopause crossings (MPCs) observed by the THEMIS spacecraft in the years 2007 to mid‐2022 using a simple Random Forest Classifier. Roughly 7% of the found crossing events deviate beyond reported errors in the stand‐off distance from the Shue et al. (1998, https://doi.org/10.1029/98JA01103) MP model and thus are termed extreme distortions. We find the occurrence of these extreme events in terms of expansion or compression of the MP to be linked to different solar wind parameters, most notably to the IMF magnitude, cone angle, velocity, Alfvén Mach number and temperature. Foreshock transients like hot‐flow anomalies and foreshock bubbles could be responsible for extreme magnetospheric expansions. The results should be incorporated into future magnetopause models and may be helpful for the reconstruction of the MP locations out of soft x‐ray images, relevant for the upcoming SMILE mission.

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“…(2015) include all IMF components,

{p}_{\mathrm{dyn}}

Section: Introductionmentioning

confidence: 99%

Study of Extreme Magnetopause Distortions Under Varying Solar Wind Conditions

et al. 2023

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“…Structures disrupting that continuous SW severely impact the bow shock and magnetopause standoff distances (Baumjohann & Treumann, 1996 ; Tátrallyay et al., 2012 ). The SW is regularly disturbed by large‐scale structures, such as stream interaction regions (SIRs) or transient events like coronal mass ejections (CMEs).…”

Section: Introductionmentioning

confidence: 99%

Magnetosheath Jet Occurrence Rate in Relation to CMEs and SIRs

et al. 2022

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Magnetosheath jets constitute a significant coupling effect between the solar wind (SW) and the magnetosphere of the Earth. In order to investigate the effects and forecasting of these jets, we present the first‐ever statistical study of the jet production during large‐scale SW structures like coronal mass ejections (CMEs), stream interaction regions (SIRs) and high speed streams (HSSs). Magnetosheath data from Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft between January 2008 and December 2020 serve as measurement source for jet detection. Two different jet definitions were used to rule out statistical biases induced by our jet detection method. For the CME and SIR + HSS lists, we used lists provided by literature and expanded on incomplete lists using OMNI data to cover the time range of May 1996 to December 2020. We find that the number and total time of observed jets decrease when CME‐sheaths hit the Earth. The number of jets is lower throughout the passing of the CME‐magnetic ejecta (ME) and recovers quickly afterward. On the other hand, the number of jets increases during SIR and HSS phases. We discuss a few possibilities to explain these statistical results.

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“…Physics-based MHD models like, for example, Liu et al (2015) include all IMF components, 𝐴𝐴 𝐴𝐴dyn and the dipole tilt as parameters to give an even better forecasting accuracy under normal solar wind conditions. Nevertheless, most models fail to predict magnetopause locations under extreme pressure conditions (e.g., Suvorova & Dmitriev, 2015;Tátrallyay et al, 2012). In these cases, other parameters can become more significant.…”

mentioning

confidence: 99%

Study of Extreme Magnetopause Distortions under Varying Solar Wind Conditions

Grimmich

Plaschke

Archer

et al. 2023

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Earth's magnetopause is the boundary layer between the solar wind and the terrestrial magnetosphere. It is an obstacle for the incoming super-magnetosonic solar wind. A bow shock (BS) upstream of the MP decelerates the solar wind and then deflects the plasma around the magnetosphere. The region between the MP and the BS is called magnetosheath (e.g., Baumjohann & Treumann, 1997). Depending on the angle between the interplanetary magnetic field (IMF) vector and the bow shock normal, the respective bow shock region (and the magnetosheath) may be denoted as quasi-parallel (angle <45°) or quasi-perpendicular (angle >45°). Upstream of the quasi-parallel bow shock, an extended foreshock region can form, permeated by waves which are excited due to the interaction of the solar wind with particles reflected at and back streaming from the BS (e.g., Eastwood et al., 2005).Dynamical changes in the solar wind and subsequently in its interaction with the BS influence the magnetosheath flow and impact the MP location and shape. In the absence of reconnection, when the MP can be described as a rotational discontinuity, the MP is well-characterized as a tangential discontinuity at which pressure balance should hold. On the magnetospheric side, the magnetic pressure is the most important contributor to that balance, while on the magnetosheath side dynamic, plasma (thermal) and magnetic pressures (from the draped IMF) contribute significantly (e.g., Shue & Chao, 2013). Thus, variations of the total pressure in the solar wind and in the magnetosheath lead to inward and outward motion of the MP. Additionally, strong southward IMF conditions lead to magnetic flux erosion from the dayside MP via magnetic reconnection and therefore inward motion of the dayside MP (

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Multispacecraft observations of the terrestrial bow shock and magnetopause during extreme solar wind disturbances

Cited by 9 publications

References 48 publications

Study of Extreme Magnetopause Distortions Under Varying Solar Wind Conditions

Study of Extreme Magnetopause Distortions Under Varying Solar Wind Conditions

Magnetosheath Jet Occurrence Rate in Relation to CMEs and SIRs

Study of Extreme Magnetopause Distortions under Varying Solar Wind Conditions

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