Observations of a new class of upstream waves with periods near 3 seconds

Le, G.; Russell, C. T.; Thomsen, M. F.; Gosling, J. T.

doi:10.1029/91ja02707

Cited by 43 publications

(33 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wave bursts at ∼3 s periods are also detected under certain conditions (Le et al 1992). The longperiod pulsations are generated by backstreaming ions in the foreshock, andtheir wave phase velocities are directed upstream in the plasma frame, but they are swept back toward the shock with the solar wind flow (e.g., Eastwood et al 2005).…”

Section: Observationsmentioning

confidence: 99%

Ion Acceleration at the Quasi-Parallel Bow Shock: Decoding the Signature of Injection

Sundberg

Haynes

Burgess

et al. 2016

ApJ

View full text Add to dashboard Cite

Collisionless shocks are efficient particle accelerators. At Earth, ions with energies exceeding 100 keV are seen upstream of the bow shock when the magnetic geometry is quasi-parallel, and large-scale supernova remnant shocks can accelerate ions into cosmic-rayenergies. This energization is attributed to diffusive shock acceleration;however, for this process to become active, the ions must first be sufficiently energized. How and where this initial acceleration takes place has been one of the key unresolved issues in shock acceleration theory. Using Cluster spacecraft observations, we study the signatures of ion reflection events in the turbulent transition layer upstream of the terrestrial bow shock, and with the support of a hybrid simulation of the shock, we show that these reflection signatures are characteristic of the first step in the ion injection process. These reflection events develop in particular in the region where the trailing edge of large-amplitude upstream waves intercept the local shock ramp and the upstream magnetic field changes from quasi-perpendicular to quasi-parallel. The dispersed ion velocity signature observed can be attributed to a rapid succession of ion reflections at this wave boundary. After the ions' initial interaction with the shock, they flow upstream along the quasi-parallel magnetic field. Each subsequent wavefront in the upstream region will sweep the ions back toward the shock, where they gain energy with each transition between the upstream and the shock wave frames. Within three to five gyroperiods, some ions have gained enough parallel velocity to escape upstream, thus completing the injection process.

show abstract

Section: Observationsmentioning

confidence: 99%

Ion Acceleration at the Quasi-Parallel Bow Shock: Decoding the Signature of Injection

Sundberg

Haynes

Burgess

et al. 2016

ApJ

View full text Add to dashboard Cite

show abstract

“…It includes gyrating ions upstream of the quasi-perpendicular shock (Paschmann et al 1982b), an electron foreshock extending far upstream of the bow shock , an ion foreshock (Asbridge et al 1968) consisting of reflected and diffuse ions (Gosling et al 1978) that precondition the solar wind (Paschmann et al 1979), Short Large Amplitude Magnetic Structures (SLAMS, Schwartz et al 1992), Hot Flow Anomalies (HFAs, Schwartz 1995), ion density holes (Parks et al 2006), 30 s period wave modulations of the upstream IMF (Greenstadt et al 1968;Fairfield 1969), 3 s waves (Le et al 1992), and a variety of higher frequency waves (whistler and Langmuir waves, see Gurnett et al 1979) and wave structures (electron solitary waves, Bale et al 1998). During the first 9 months of operations, all of these phenomena have been observed except for high frequency wave phenomena which THEMIS does not measure.…”

Section: Bow Shockmentioning

confidence: 99%

THEMIS ESA First Science Results and Performance Issues

et al. 2008

View full text Add to dashboard Cite

Early observations by the THEMIS ESA plasma instrument have revealed new details of the dayside magnetosphere. As an introduction to THEMIS plasma data, this paper presents observations of plasmaspheric plumes, ionospheric ion outflows, field line resonances, structure at the low latitude boundary layer, flux transfer events at the magnetopause, and wave and particle interactions at the bow shock. These observations demonstrate the capabilities of the plasma sensors and the synergy of its measurements with the other THEMIS experiments. In addition, the paper includes discussions of various performance issues with the ESA instrument such as sources of sensor background, measurement limitations, and data formatting problems. These initial results demonstrate successful achievement of all measurement objectives for the plasma instrument.

show abstract

“…The existence of a new category of waves, called '3s waves' (Le et al, 1992), has also been reported. These waves are circularly polarised, right handed and have periods of 2 -5 s in the spacecraft frame.…”

mentioning

confidence: 97%

The Foreshock

et al. 2005

View full text Add to dashboard Cite

Although collisionless shocks primarily exist to mediate the flow of supermagnetosonic plasma, they also act as sites for particle acceleration. It is now well known that for certain magnetic field geometries, a portion of the inflowing plasma returns to the upstream region rather than being processed by the shock and passing irreversibly downstream. The combination of the inflowing plasma and this counterstreaming component upstream of the shock is subject to a number of plasma instabilities, leading to the generation of waves. These waves interact in a highly complex manner with the ions and electrons making up the plasma and can cause part of the plasma distribution to reach high energies.The region of space upstream of the bow shock, magnetically connected to the shock and filled with particles backstreaming from the shock is known as the foreshock. As discussed in Balogh et al. (2005), the bow shock can be classified into quasi-perpendicular and quasi-parallel shock regions according to the angle θ Bn between the shock normal n and the direction of the solar wind magnetic field B. For the quasi-perpendicular bow shock (θ Bn > 45 • ), the foreshock is restricted to the shock foot, while in the quasi-parallel part of the bow shock (θ Bn < 45 • ), it

show abstract

Observations of a new class of upstream waves with periods near 3 seconds

Cited by 43 publications

References 21 publications

Ion Acceleration at the Quasi-Parallel Bow Shock: Decoding the Signature of Injection

Ion Acceleration at the Quasi-Parallel Bow Shock: Decoding the Signature of Injection

THEMIS ESA First Science Results and Performance Issues

The Foreshock

Contact Info

Product

Resources

About