Observations of an intermediate shock in interplanetary space

Chao, J. K.; Lyu, L. H.; Wu, B. H.; Lazarus, A. J.; Chang, Tom; Lepping, R. P.

doi:10.1029/93ja01609

Cited by 34 publications

(36 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, Wu (1987) showed that, via simulation of a set of resistive MHD equations, that the intermediate shock can be stable in some situations. In addition, Chao et al (1993) identified an intermediate shock near 9 AU from the Voyager 1 plasma and magnetic field data. Whang (1987) suggested that the decrease in the Alfvén speed at increasing heliocentric distance causes the normal Alfvén Mach number of a forward slow shock to become greater than 1, and the shock should eventually evolve from a slow shock into a fast shock.…”

Section: Introductionmentioning

confidence: 99%

Slow shock interactions in the heliosphere using an adaptive grid MHD model

Dryer

2005

Ann. Geophys.

View full text Add to dashboard Cite

Abstract.A one-dimensional (1-D), time-dependent, adaptive-grid MHD model with solar wind structure has been used in the past to study the interaction of shocks. In the present study, we wish to study some fundamental processes that may be associated with slow shock genesis and their possible interactions with other discontinuities. This adaptivegrid model, suitable for appropriate spatial and temporal numerical simulations, is used for this purpose because its finer grid sizes in the vicinity of the steep gradients at shocks make it possible to delineate the physical parameters on both sides of the shocks. We found that a perturbation with deceleration of solar wind will generate an ensemble consisting of a forward slow shock, a fast forward wave and a reverse slow shock. On the other hand, a perturbation with an increase in acceleration of solar wind will generate both a slow shock and a fast shock. These two perturbations, although not unique, may be representative of momentum and pressure changes at the solar surface.During the transition of a fast shock overtaking a slow shock from behind, the slow shock might disappear temporarily. Also, during the process of the merging of two slow shocks, a slow shock-like structure is formed first; later, the slow shock-like structure evolves into an intermediate shock-like structure. This intermediate shock-like structure then evolves into an intermediate wave and a slow shock-like structure. Finally, the slow shock-like structure evolves into a slow shock, but the intermediate wave disappears by interacting with the non-uniform solar wind. This complex behavior demonstrates the non-unique nature of the formation of slow shocks, intermediate shocks and their derivative structures.We emphasize the main aim of this work to be both: (a) non-unique input physical parameters to explain the paucity of observed slow shocks, as well as (b) the impossibility of backward tracing to the history of input boundary conditions in view of the present inability to describe unambiguous inputs at the Sun.

show abstract

Section: Introductionmentioning

confidence: 99%

Slow shock interactions in the heliosphere using an adaptive grid MHD model

Dryer

2005

Ann. Geophys.

View full text Add to dashboard Cite

show abstract

“…Over the past more than four decades, there have been a large number of numerical investigations for ISs. In spite of evolutionary conditions, ISs are commonly observed to be stable shocks in numerical simulations (e.g., Wu 1987;Wu & Hada 1991;Takahashi et al 2013Takahashi et al , 2014, and two interplanetary ISs have been observed and reported (Chao et al 1993;Feng & Wang 2008). However, both ISs were identified through fitting the R-H relations based on one spacecraft observation.…”

Section: Discussionmentioning

confidence: 99%

“…However, observations of ISs are very rare; to our knowledge, only two cases have been reported. One is a  2 4 type IS, which was observed in 1980 when Voyager 1 was approximately at 9 au from the Sun (Chao et al 1993); the other is a  2 3 type IS, which was detected at 4.5 au by Voyager 2 in 1979 (Feng & Wang 2008). Both ISs were observed far away from the Sun, and they were detected only by one spacecraft, so they were identified based only on fitting the R-H relations.…”

Section: Introductionmentioning

confidence: 99%

Observations of an Interplanetary Intermediate Shock Associated With a Magnetic Reconnection Exhaust

Feng

Wang

et al. 2016

ApJ

View full text Add to dashboard Cite

Two intermediate shocks (ISs) in interplanetary space have been identified via one spacecraft observation. However, Feng et al. suggested that the analysis using a single spacecraft observation based only on the RankineHugoniot (R-H) relations could misinterpret a tangential discontinuity (TD) as an IS. The misinterpretation can be fixed if two spacecraft observations are available. In this paper, we report an IS-like discontinuity associated with a magnetic reconnection exhaust, which was observed by Wind on 2000 August 9 at 1 au. We investigated this discontinuity by fitting the R-H relations and referring to the Advanced Composition Explorer (ACE) observations. As a result, we found that the observed magnetic field and plasma data satisfy the R-H relations well, and the discontinuity satisfies all the requirements of the  2 3 type IS. Although the discontinuity cannot be identified strictly by using two spacecraft observations, in light of the ACE observations we consider that the discontinuity should be an IS rather than a TD.

show abstract

“…Traditionally ͑Akhiezer, Liubarski, and Polovin, 9 Germain, 10 Jeffrey and Taniuti 11 ͒, this failure of the test of evolutionarity was used to rule out the physical reality of intermediate shocks. However, after Wu 13 showed intermediate shocks to arise in numerical solutions of the dissipative MHD equations, a flurry of numerical and observational papers appeared on the structure and formation of intermediate shocks, [25][26][27][28][29] on their astrophysical implications, 30,31 on their relationship with magnetic reconnection, 32,33 on their significance for the Riemann problem, [34][35][36] on their occurrence in bow-shock flows, 37 and their possible breakup. 38 As mentioned in the Introduction, Falle and Komissarov 16 presented arguments to stick to the traditional view point.…”

Section: -17mentioning

confidence: 99%

Time reversal duality of magnetohydrodynamic shocks

Goedbloed

2008

Physics of Plasmas

View full text Add to dashboard Cite

The shock conditions in magnetohydrodynamics ͑MHD͒ are reduced to their most concise, three-parameter, distilled form by consistent use of the scale independence of the MHD equations and of the de Hoffmann-Teller transformation. They then exhibit a distinct time reversal duality between entropy-allowed shocks and entropy-forbidden jumps. This yields a new classification of MHD shocks by means of the monotonicity properties with respect to upstream and downstream Alfvén Mach numbers, it exhibits the central role of intermediate discontinuities, and permits straightforward construction of all relevant dimensionless quantities of the shocks. An exhaustive overview is presented of solutions in the different parameter regimes.

show abstract

Observations of an intermediate shock in interplanetary space

Cited by 34 publications

References 21 publications

Slow shock interactions in the heliosphere using an adaptive grid MHD model

Slow shock interactions in the heliosphere using an adaptive grid MHD model

Observations of an Interplanetary Intermediate Shock Associated With a Magnetic Reconnection Exhaust

Time reversal duality of magnetohydrodynamic shocks

Contact Info

Product

Resources

About