Zero outward flow velocity for plasma in a heliosheath transition layer

  title={Zero outward flow velocity for plasma in a heliosheath transition layer},
  author={Stamatios M. Krimigis and Edmond C. Roelof and R. Decker and Matthew E. Hill},
Voyager 1 has been in the reservoir of energetic ions and electrons that constitutes the heliosheath since it crossed the solar wind termination shock on 16 December 2004 at a distance from the Sun of 94 astronomical units (1 au = 1.5 × 108 km). It is now ∼22 au past the termination shock crossing. The bulk velocity of the plasma in the radial–transverse plane has been determined using measurements of the anisotropy of the convected energetic ion distribution. Here we report that the radial… 

No meridional plasma flow in the heliosheath transition region

It is reported that, contrary to expectations, Voyager 1 observed a gradual slowing-down of radial plasma flow in the heliosheath to near-zero velocity, which yielded a meridional flow velocity of +3 ± 11 km s−1, that is, one consistent with zero within statistical uncertainties.

The structure of the Heliopause

Voyager 1 has explored the solar wind-interstellar medium interaction region between the Terminal Shock and Heliopause, following the intensity distribution of the shock accelerated anomalous


Recent observations from Voyager 1 in the nose region of the heliosheath, an area created by the motion of the Sun through the local interstellar medium, have revealed that: (1) beyond ∼113 AU from

Global Structure and Dominant Particle Acceleration Mechanism of the Heliosheath: Definitive Conclusions

During its exploration of the heliosheath, the region that lies between the termination shock of the solar wind and the heliopause that separates the solar wind from the local interstellar medium,

Magnetic Field Observations as Voyager 1 Entered the Heliosheath Depletion Region

The observations indicate that Voyager 1 had not crossed the heliopause but had entered a region in the heliosphere that serves as a magnetic highway along which low-energy ions from inside stream away and galactic cosmic rays flow in from interstellar space.


Since April of 2010, Voyager 1 has been immersed in a region of near zero radial flows, where the solar wind seems to have stopped. The existence of this region contradicts current models that

Voyager 2 plasma observations of the heliopause and interstellar medium

The solar wind blows outwards from the Sun and forms a bubble of solar material in the interstellar medium. The heliopause (HP) is the boundary that divides the hot tenuous solar wind plasma in the

Search for the Exit: Voyager 1 at Heliosphere’s Border with the Galaxy

Measurements of energetic (>40 kiloelectron volts) charged particles on Voyager 1 from the interface region between the heliosheath, dominated by heated solar plasma, and the local interstellar medium, which is expected to contain cold nonsolar plasma and the galactic magnetic field.

A model for the nose region of the heliosheath

The Voyager 1 spacecraft is currently in the vicinity of the heliopause, which separates the heliosphere from the local interstellar medium. There has been a precipitous decrease in particles

Energetic Charged Particles in the Heliosphere from 1-120 AU Measured by the Voyager Spacecraft

For nearly 35 years the Voyager Spacecraft have been pursuing their epic journey to the boundaries of the heliosphere and interstellar (IS) space beyond. The remarkable observations of Jupiter,



Crossing the Termination Shock into the Heliosheath: Magnetic Fields

Magnetic fields measured by Voyager 1 show that the spacecraft crossed or was crossed by the termination shock on about 16 December 2004 at 94.0 astronomical units, and the cosmic ray intensity increased when B was relatively large in the heliosheath.

Voyager 1 in the Foreshock, Termination Shock, and Heliosheath

Observations from Voyager 1 are interpreted as evidence that V1 was crossed by the TS on 2004/351 (during a tracking gap) at 94.0 astronomical units, evidently as the shock was moving radially inward in response to decreasing solar wind ram pressure, and that V 1 has remained in the heliosheath until at least mid-2005.

Voyager 1 Explores the Termination Shock Region and the Heliosheath Beyond

The intensity of anomalous cosmic ray (ACR) helium did not peak at the shock, indicating that the ACR source is not in the shock region local to Voyager 1, and the intensities of ∼10–megaelectron volt electrons, ACRs, and galactic cosmic rays have steadily increased since late 2004.

The Dynamic Heliosphere: Outstanding Issues

Properties of the heliospheric interface, a complex product of an interaction between charged and neutral particles and magnetic fields in the heliosphere and surrounding Circumheliospheric Medium,

Physics of the Solar Wind–Local Interstellar Medium Interaction: Role of Magnetic Fields

The interaction of the solar wind with the local interstellar medium is characterized by the self-consistent coupling of solar wind plasma, both upstream and downstream of the heliospheric

Kinetic-Gasdynamic Modeling of the Heliospheric Interface

Heliospheric energetic neutral atoms (ENAs) that will be measured by the Interstellar Boundary Explorer (IBEX) originate from the heliosheath. The heliosheath is formed as a result of the interaction

Imaging the Interaction of the Heliosphere with the Interstellar Medium from Saturn with Cassini

The shape of the heliosphere is not consistent with that of a comet aligned in the direction of the Sun's travel through the galaxy as was previously thought, and the model they have developed suggests that the interstellar magnetic field plays a stronger role than previously thought.

Implications of Generalized Rankine‐Hugoniot Conditions for the PUI Population at the Voyager 2 Termination Shock

The Rankine‐Hugoniot (R‐H) jump conditions at the heliospheric termination shock provide a means of knitting together the in situ measurements from Voyager 2 (VGR2) with the remote sensing of the

ENA (E>5 keV) Images from Cassini and Voyager “ground truth”: Suprathermal Pressure in the Heliosheath

Maps of energetic neutral atoms (ENA) of the heliosphere from Cassini [1] have been constructed spanning the energy range ∼5≤E≤55 keV, and show a “Belt” in the sky of ∼100° FWHM. Similarly, maps >6

Role of Magnetic Fields in Star Formation

  • R. Crutcher
  • Physics
    Proceedings of the International Astronomical Union
  • 2009
Abstract I describe two recent projects to test star formation theory using Zeeman observations. First, using Bayesian analysis, the probability distribution function of the magnitude of the total