Quasi-parallel Shock Structure and Processes

Burgess, David; Lucek, E.; Scholer, M.; Bale, S. D.; Balikhin, M. A.; Balogh, A.; Horbury, T. S.; Krasnoselskikh, V.; Kucharek, H.; Lembège, Bertrand; Möbius, E.; Schwartz, S. J.; Thomsen, M. F.; Walker, S. N.

doi:10.1007/s11214-005-3832-3

Cited by 129 publications

(127 citation statements)

References 35 publications

Supporting

Mentioning

122

Contrasting

Order By: Relevance

“…the angle between the shock normal and the magnetic field lines upstream is 60 • as compared to 15 • , for the first shock (S1). Here, the values of θ indicate that shock S1 is quasi-parallel (θ < 45 • ) and therefore should be associated with extended foreshock regions, whereas the shock transitions are typically more gradual; the jumps in the solar wind plasma parameters and in the magnetic field magnitude are less significant than at quasi-perpendicular shocks (Burgess et al, 2005;Kruparova et al, 2013), where θ > 45 • .…”

Section: Sudden Storm Commencementmentioning

confidence: 89%

Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13 – 14 June 2012

2018

View full text Add to dashboard Cite

We report on the kinematics of two interacting CMEs observed on 13 and 14 June 2012. Both CMEs originated from the same active region NOAA 11504. After their launches which were separated by several hours, they were observed to interact at a distance of 100 R from the Sun. The interaction led to a moderate geomagnetic storm at the Earth with D st index of approximately, -86 nT. The kinematics of the two CMEs is estimated using data from the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory (STEREO). Assuming a head-on collision scenario, we find that the collision is inelastic in nature. Further, the signatures of their interaction are examined using the in situ observations obtained by Wind and the Advance Composition Explorer (ACE) spacecraft. It is also found that this interaction event led to the strongest sudden storm commencement (SSC) (≈ 150 nT) of the present Solar Cycle 24. The SSC was of long duration, approximately 20 hours. The role of interacting CMEs in enhancing the geoeffectiveness is examined.

show abstract

Section: Sudden Storm Commencementmentioning

confidence: 89%

Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13 – 14 June 2012

2018

View full text Add to dashboard Cite

show abstract

“…Reformation of the quasi-parallel shock caused by so-called SLAMs (Short Large Amplitude Magnetic Structures; Schwartz and Burgess [1991], Burgess et al [2005]) may generate pulsations that may propagate to large distances. However, these events do not usually occur periodically.…”

Section: Discussionmentioning

confidence: 99%

Magnetosheath for almost‐aligned solar wind magnetic field and flow vectors: Wind observations across the dawnside magnetosheath at X = −12 Re

et al. 2010

Self Cite

View full text Add to dashboard Cite

[1] While there are many approximations describing the flow of the solar wind past the magnetosphere in the magnetosheath, the case of perfectly aligned (parallel or antiparallel) interplanetary magnetic field (IMF) and solar wind flow vectors can be treated exactly in a magnetohydrodynamic (MHD) approach. In this work we examine a case of nearly-opposed (to within 15°) interplanetary field and flow vectors, which occurred on October 24-25, 2001 during passage of the last interplanetary coronal mass ejection in an ejecta merger. Interplanetary data are from the ACE spacecraft. Simultaneously Wind was crossing the near-Earth (X ∼ −13 Re) geomagnetic tail and subsequently made an approximately 5-hour-long magnetosheath crossing close to the ecliptic plane (Z = −0.7 Re). Geomagnetic activity was returning steadily to quiet, "ground" conditions. We first compare the predictions of the Spreiter and Rizzi theory with the Wind magnetosheath observations and find fair agreement, in particular as regards the proportionality of the magnetic field strength and the product of the plasma density and bulk speed. We then carry out a small-perturbation analysis of the Spreiter and Rizzi solution to account for the small IMF components perpendicular to the flow vector. The resulting expression is compared to the time series of the observations and satisfactory agreement is obtained. We also present and discuss observations in the dawnside boundary layer of pulsed, high-speed (v ∼ 600 km/s) flows exceeding the solar wind flow speeds. We examine various generating mechanisms and suggest that the most likely cause is a wave of frequency 3.2 mHz excited at the inner edge of the boundary layer by the Kelvin-Helmholtz instability.

show abstract

“…Collisionless shocks are of great interests in space physics, plasma physics and astrophysics since many theoretical, numerical and experimental studies have already evidenced that in the shock transition the bulk flow energy of plasmas is converted irreversibly into thermal energy (Sagdeev 1966;Lembège et al 2004;Burgess et al 2005). During the conversion process, the interaction between the electromagnetic fields and particles replaces the role played by collisions in a normal hydrodynamics.…”

Section: Introductionmentioning

confidence: 99%

Contributions to the cross shock electric field at supercritical perpendicular shocks: impact of the pickup ions

Yang¹,

Han²,

Yang³

et al. 2012

Astrophys Space Sci

View full text Add to dashboard Cite

A particle-in-cell code is used to examine contributions of the pickup ions (PIs) and the solar wind ions (SWs) to the cross shock electric field at the supercritical, perpendicular shocks. The code treats the pickup ions self-consistently as a third component. Herein, two different runs with relative pickup ion density of 25% and 55% are presented in this paper. Present preliminary results show that: (1) in the low percentage (25%) pickup ion case, the shock front is nonstationary. During the evolution of this perpendicular shock, a nonstationary foot resulting from the reflected solar wind ions is formed in front of the old ramp, and its amplitude becomes larger and larger. At last, the nonstationary foot grows up into a new ramp and exceeds the old one. Such a nonstationary process can be formed periodically. When the new ramp begins to be formed in front of the old ramp, the Hall term mainly contributed by the solar wind ions becomes more and more important. The electric field E x is dominated by the Hall term when the new ramp exceeds the old one. Furthermore, an extended and stationary foot in pickup ion gyro-scale is located upstream of the nonstationary/self-reforming region within the shock front, and is always dominated by the Lorentz term contributed by the pickup ions; (2) in the high percentage (55%) pickup ion case, the amplitude of the stationary foot is increased as expected. One striking point is that the nonstationary region of the shock front evidenced by the self-reformation disappears. Instead, a stationary extended foot dominated by Lorentz term contributed by the pickup ions, and a stationary ramp dominated by Hall term contributed by the solar wind ions are clearly evidenced. The significance of the cross electric field on ion dynamics is also discussed.

show abstract

Quasi-parallel Shock Structure and Processes

Cited by 129 publications

References 35 publications

Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13 – 14 June 2012

Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13 – 14 June 2012

Magnetosheath for almost‐aligned solar wind magnetic field and flow vectors: Wind observations across the dawnside magnetosheath at X = −12 Re

Contributions to the cross shock electric field at supercritical perpendicular shocks: impact of the pickup ions

Contact Info

Product

Resources

About