High‐latitude magnetic reconnection in sub‐Alfvénic flow: Interball Tail observations on May 29, 1996

Avanov, L. A.; Смирнов, В. Н.; Waite, J. H.; Fuselier, S. A.; Вайсберг, О. Л.

doi:10.1029/2000ja000460

Cited by 43 publications

(48 citation statements)

References 30 publications

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“…The observational data for a particular case (Avanov et al, 2001) indicate that there is a nonzero bulk ion flux, but smaller than for the MHD rotational discontinuity, across the discontinuity, while outside the CS the ion distribution function has a characteristic counterstreaming feature; this corresponds to the mentioned "intermediate" situation.…”

Section: Planar Discontinuities In Collisionless Plasmamentioning

confidence: 99%

Forced current sheet structure, formation and evolution: application to magnetic reconnection in the magnetosphere

Domrin

Kropotkin

2004

Ann. Geophys.

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Part of Special Issue "Spatio-temporal analysis and multipoint measurements in space"Abstract. By means of a simulation model, the earlier predicted nonlinear kinetic structure, a Forced Kinetic Current Sheet (FKCS), with extremely anisotropic ion distributions, is shown to appear as a result of a fast nonlinear process of transition from a previously existing equilibrium. This occurs under triggering action of a weak MHD disturbance that is applied at the boundary of the simulation box. In the FKCS, current is carried by initially cold ions which are brought into the CS by convection from both sides, and accelerated inside the CS. The process then appears to be spontaneously self-sustained, as a MHD disturbance of a rarefaction wave type propagates over the background plasma outside the CS. Comparable to the Alfvénic discontinuity in MHD, transformation of electromagnetic energy into the energy of plasma flows occurs at the FKCS. But unlike the MHD case, "free" energy is produced here: dissipation should occur later, through particle interaction with turbulent waves generated by unstable ion distribution being formed by the FKCS action. In this way, an effect of magnetic field "annihilation" appears, required for fast magnetic reconnection. Application of the theory to observations at the magnetopause and in the magnetotail is considered.

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Section: Planar Discontinuities In Collisionless Plasmamentioning

confidence: 99%

Forced current sheet structure, formation and evolution: application to magnetic reconnection in the magnetosphere

Domrin

Kropotkin

2004

Ann. Geophys.

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“…One can see a systematic difference in the measured and model V x between the MP and 03:30 UT; after that time V x fits the model well. Detailed study of high-resolution ion data by Avanov et al (2001) provides further proof for the registration of the features predicted by the model reconnection site being downtail of Interball (Alfvénic field-aligned flows in the de Hofmann-Teller frame, stress balance fulfilling, etc.). Now we would like to address the problem of the mechanism for the MSH plasma penetration into the cusp (see Fig.…”

Section: Comparison With Mhd Modelmentioning

confidence: 99%

“…Panel (e) displays GSE V x and V z components of ion velocity from the MHD model of Fedder et al (1995) (black trace, see Sect. 2.2) and measurements by SKA-1 ion spectrometer (see details of the plasma data in Avanov et al, 2001), which are colored red. Panel (f) shows the power contained in the magnetic field variations, Df , and the standard deviation of the magnetic field magnitude, Dm.…”

Section: Event Descriptionmentioning

confidence: 99%

“…There are a number of previous studies of this event, but they have concentrated on single spacecraft data (see, e.g. Russell et al, 1998;Savin et al, 1998a;Chandler et al, 1999;Avanov et al, 2001). In our study Interball-1 serves as the upstream MSH monitor for Polar in the TBL and for HEO-095 and DMSP in the inner cusp (see Grande et al, 1997) and ionosphere, respectively.…”

Section: Introduction and Definitionsmentioning

confidence: 99%

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Magnetosheath-cusp interface

Savin

Zelenyǐ²,

Романов³

et al. 2004

Ann. Geophys.

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Abstract. We advance the achievements of Interball-1 and other contemporary missions in exploration of the magnetosheath-cusp interface. Extensive discussion of published results is accompanied by presentation of new data from a case study and a comparison of those data within the broader context of three-year magnetopause (MP) crossings by Interball-1. Multi-spacecraft boundary layer studies reveal that in ∼80% of the cases the interaction of the magnetosheath (MSH) flow with the high latitude MP produces a layer containing strong nonlinear turbulence, called the turbulent boundary layer (TBL). The TBL contains wave trains with flows at approximately the Alfvén speed along field lines and "diamagnetic bubbles" with small magnetic fields inside. A comparison of the multi-point measurements obtained on 29 May 1996 with a global MHD model indicates that three types of populating processes should be operative:-large-scale (∼few R E ) anti-parallel merging at sites remote from the cusp; -medium-scale (few thousand km) local TBL-merging of fields that are anti-parallel on average;Correspondence to: S. Savin (ssavin@iki.rssi.ru) -small-scale (few hundred km) bursty reconnection of fluctuating magnetic fields, representing a continuous mechanism for MSH plasma inflow into the magnetosphere, which could dominate in quasi-steady cases.The lowest frequency (∼1-2 mHz) TBL fluctuations are traced throughout the magnetosheath from the post-bow shock region up to the inner magnetopause border. The resonance of these fluctuations with dayside flux tubes might provide an effective correlative link for the entire dayside region of the solar wind interaction with the magnetopause and cusp ionosphere. The TBL disturbances are characterized by kinked, double-sloped wave power spectra and, most probably, three-wave cascading. Both elliptical polarization and nearly Alfvénic phase velocities with characteristic dispersion indicate the kinetic Alfvénic nature of the TBL waves. The three-wave phase coupling could effectively support the self-organization of the TBL plasma by means of coherent resonant-like structures. The estimated characteristic scale of the "resonator" is of the order of the TBL dimension over the cusps. Inverse cascades of kinetic Alfvén waves are proposed for forming the larger scale "organizing" structures, which in turn synchronize all nonlinear cascades within the TBL in a self-consistent manner. This infers a qualitative differ-184 S. Savin et al.: Magnetosheath-cusp interface ence from the traditional approach, wherein the MSH/cusp interaction is regarded as a linear superposition of magnetospheric responses on the solar wind or MSH disturbances.

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“…While single-spacecraft measurements have provided ample in-situ evidence for the occurrence of reconnection at the MP (e.g. Paschmann et al, 1979Paschmann et al, , 1986Sonnerup et al, 1981;Gosling et al, 1991;Smith and Rodgers, 1991;Fuselier et al, 1991;Onsager et al, 2001;Avanov et al, 2001;Mozer et al, 2002), little is known about the large-scale spatial and temporal nature of reconnection from single-point in-situ observations. For example, it is not known whether reconnection at the MP is intrinsically intermittent or continuous.…”

Section: Introductionmentioning

confidence: 99%

Cluster observations of continuous reconnection at the magnetopause under steady interplanetary magnetic field conditions

et al. 2004

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Abstract. On 26 January 2001, the Cluster spacecraft detected high-speed plasma jets at multiple crossings of the high-latitude duskside magnetopause (MP) and boundary layer (BL) over a period of more than 2 h. The 4 spacecraft combined spent more than half of this time in the MP/BL and jets were observed whenever a spacecraft was in the MP. These observations were made under steady southward and dawnward interplanetary magnetic field (IMF) conditions. The magnetic shear across the local MP was ∼100 • and β∼1 in the adjacent magnetosheath. The jet velocity is in remarkable agreement with reconnection prediction throughout the entire interval, except for one crossing that had no ion measurements inside the current layer. The flow speed measured in the deHoffmann Teller frame is 90% of the Alfvén speed on average for the 10 complete MP current layer crossings that are resolved by the ion measurements. These findings strongly suggest that reconnection was continuously active for more than two hours. The jets were directed persistently in the same northward and anti-sunward direction, implying that the X-line was always below the spacecraft. This feature is inconsistent with patchy and random reconnection or convecting multiple X-lines. The majority of MP/BL crossings in this two-hour interval were partial crossings, implying that they are caused by bulges sliding along the MP, not by inward-outward motion of a uniformly thin MP/BL. The presence of the bulges suggests that, although reconnection is continuously active under steady IMF conditions, its rate may be modulated. The present investigation also reveals that (1) the predicted ion D-shaped distributions are absent in all reconnection jets on this day, (2) the electric field fluctuations are larger in the reconnecting MP than in the magnetosheath proper, but their amplitudes never exceed 20 mV/m, (3) the ion-electron differential motion is ∼20 km/s for the Correspondence to: T. D. Phan (phan@ssl.berkeley.edu) observed MP current density of ∼50 nA/m 2 (deduced from ∇×B), thus inconsequential for the deHoffmann-Teller and Walén analyses, (4) flows in an isolated flux transfer event (FTE) are directed in the same direction as the MP jets and satisfy the Walén relation, suggesting that this FTE is also generated by reconnection. Finally, the present event cannot be used to evaluate the validity of component or anti-parallel merging models because, although the magnetic shear at the local MP was ∼100 • ( 180 • ), the X-line may be located more than 9 R E away (in the opposite hemisphere), where the shear could be substantially different.

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High‐latitude magnetic reconnection in sub‐Alfvénic flow: Interball Tail observations on May 29, 1996

Cited by 43 publications

References 30 publications

Forced current sheet structure, formation and evolution: application to magnetic reconnection in the magnetosphere

Forced current sheet structure, formation and evolution: application to magnetic reconnection in the magnetosphere

Magnetosheath-cusp interface

Cluster observations of continuous reconnection at the magnetopause under steady interplanetary magnetic field conditions

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