Solar wind controls on Mercury's magnetospheric cusp

2017 ◽  
Vol 122 (6) ◽  
pp. 6150-6164 ◽  
Author(s):  
Maosheng He ◽  
Joachim Vogt ◽  
Daniel Heyner ◽  
Jun Zhong
Keyword(s):  
Solar Wind ◽  
Magnetospheric Cusp

scholarly journals MESSENGER observations of planetary ion enhancements at Mercury’s northern magnetospheric cusp during Flux Transfer Event Showers

2021 ◽  
Author(s):  
Weijie Sun ◽  
James Slavin ◽  
Anna Milillo ◽  
Ryan Dewey ◽  
Stefano Orsini ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Transfer Event ◽  
Order Of Magnitude ◽  
In Situ Observations ◽  
Flux Transfer ◽  
Magnetospheric Cusp ◽  
Upward Moving ◽  
Entry Layer

Abstract At Mercury, several processes can release ions and neutrals out of the planet’s surface. Here we present enhancements of dayside planetary ions in the solar wind entry layer during flux transfer event (FTE) “showers” near Mercury’s northern magnetospheric cusp. In this entry layer, solar wind ions are accelerated and move downward (i.e. planetward) toward the cusps, which sputter upward-moving planetary ions within 1 minute. The precipitation rate is enhanced by an order of magnitude during FTE showers and the neutral density of the exosphere can vary by >10% due to this FTE-driven sputtering. These in situ observations of enhanced planetary ions in the entry layer likely correspond to an escape channel of Mercury’s planetary ions, and the large-scale variations of the exosphere observed on minute-timescales by ground-based telescopes. Comprehensive, future multi-point measurements made by BepiColombo will greatly enhance our understanding of the processes contributing to Mercury’s dynamic exosphere and magnetosphere.

scholarly journals Cluster observations of a structured magnetospheric cusp

2006 ◽  
Vol 24 (3) ◽  
pp. 1015-1027 ◽  
Author(s):  
N. Balan ◽  
H. Alleyne ◽  
S. Walker ◽  
H. Réme ◽  
P. M. E. Décréau ◽  
...  
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Time Sequence ◽  
Solar Wind Dynamic Pressure ◽  
Reverse Time ◽  
Ion Flow ◽  
Cusp Region ◽  
Cluster Data ◽  
Magnetospheric Cusp ◽  
Bulk Plasma

Abstract. On 18 April 2002 the Cluster spacecraft crossed through the northern outer magnetospheric cusp region during 16:25-17:55 UT when the solar wind dynamic pressure was rather low (<2 nPa) and IMF Bz was more negative than IMF By. The Cluster data from the FGM, CIS, PEACE, EFW, WHISPER and STAFF instruments reveal that the cusp is structured with three anti-sunward ion flow events of durations ≈1.5, 17.5 and 19.0 min, with bulk plasma flow roughly parallel to the magnetopause toward north. The ion and electron densities within the events are much greater than those outside. The zonal electric field in the ion flow events turns eastward as expected from V×B effect. The sharp inward boundaries of the ion flow events cross the four spacecraft in one time sequence, and the outward boundaries of the events cross the spacecraft in the reverse time sequence. The observations studied using magnetosphere and magnetopause models suggest that the structured cusp is a temporal feature that arises due to three inward and outward movements of the magnetopause by about 1.5RE so that Cluster, while crossing through the cusp, happened to be in the magnetosheath (ion flow event) and cusp alternately. The magnetopause moved due to the changes in the solar wind dynamic pressure by up to 100%.

scholarly journals Energetic particle sounding of the magnetospheric cusp with ISEE-1

2007 ◽  
Vol 25 (5) ◽  
pp. 1175-1182 ◽  
Author(s):  
K. E. Whitaker ◽  
T. A. Fritz ◽  
J. Chen ◽  
M. Klida
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Pitch Angle ◽  
Energetic Particle ◽  
Bow Shock ◽  
Local Magnetic Field ◽  
Slow Solar Wind ◽  
Energetic Ions ◽  
Cusp Region ◽  
Magnetospheric Cusp

Abstract. Observations on 30 October 1978 show the ISEE-1 spacecraft passing though the high-altitude dayside northern magnetospheric cusp region from roughly 16:00 to 18:30 UT, during a slow solar wind period (~380 km/s). More than two orders of magnitude enhancements of the cusp energetic particle (CEP) fluxes were observed along with a depressed and turbulent local magnetic field. The observed variations of the pitch angle distributions (PAD) provide a unique opportunity to determine the structure of the cusp and the origin of the CEP. Through a boundary sounding technique, the location and orientation of the cusp poleward (or backside) boundary was observed for almost 10 min during which time it appeared initially to be stationary in the GSM/GSE X-direction and then moved sunward about 0.12 Earth radii (RE). The orientation remained approximately perpendicular to the GSM/GSE X-axis until it was observed to rotate by 60 degrees in ~3 min before ISEE-1 was fully inside the cusp cavity. The cavity itself was filled with CEP fluxes displaying large anisotropies, indicative of their source being located below (Earthward) of the satellite location. The spacecraft entered from the backside of the cusp, then traveled ~4 RE through the cavity, and exited through the "top" of the cavity leaving a region of energetic ions below. The PADs demonstrate that the bow shock cannot be the main source of the observed CEPs. The CEP fluxes were measured at about 8.5 h MLT when the IMF had both an 8–10 nT duskward and southward component.

scholarly journals Energetic particles observed by ISEE-1 and ISEE-2 in a cusp diamagnetic cavity on 29 September 1978

2007 ◽  
Vol 25 (12) ◽  
pp. 2633-2640 ◽  
Author(s):  
B. M. Walsh ◽  
T. A. Fritz ◽  
N. M. Lender ◽  
J. Chen ◽  
K. E. Whitaker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Pitch Angle ◽  
Energetic Particle ◽  
Electron Flux ◽  
Energetic Particles ◽  
Local Magnetic Field ◽  
Local Source ◽  
Magnetospheric Cusp ◽  
The Magnetic Field

Abstract. Observations by the ISEE-1 and ISEE-2 spacecraft on 29 September 1978 show large CEP (Cusp Energetic Particle) fluxes while passing through the dayside magnetospheric cusp in near coincident orbits. The event was observed around 11:00 MLT between roughly 12:30 and 13:00 UT by ISEE-1 and 12:00 and 13:00 UT by ISEE-2. During these periods, both electron and ion fluxes increased by more than two orders of magnitude, with the electron flux showing a strong peak at a pitch angle of 90°. The solar wind was ~710 km s−1 and the Dst was ~−200 nT, suggesting the occurrence of a strong geomagnetic storm. The ISEE-1 and ISEE-2 observations, however, show no time-energy dispersion of the CEPs, leading us to believe that these particles could not be the result of substorm processes in the magnetotail. The local magnetic field was depressed and extremely turbulent. Changes in the magnitude of the magnetic field anticorrelate closely to variations of the electron flux. The observations in electron flux peaking at 90° and the close anticorrelation between the local magnetic field strength and electron flux are unique and provide evidence of a potential local source for these energetic particles.

Solar wind plasma injection at the dayside magnetospheric cusp

1977 ◽  
Vol 82 (4) ◽  
pp. 479-491 ◽  
Author(s):  
P. H. Reiff ◽  
T. W. Hill ◽  
J. L. Burch
Keyword(s):  
Solar Wind ◽  
Solar Wind Plasma ◽  
Plasma Injection ◽  
Magnetospheric Cusp

scholarly journals Coordinated ground-based, low altitude satellite and Cluster observations on global and local scales during a transient post-noon sector excursion of the magnetospheric cusp

2001 ◽  
Vol 19 (10/12) ◽  
pp. 1367-1398 ◽  
Author(s):  
H. J. Opgenoorth ◽  
M. Lockwood ◽  
D. Alcaydé ◽  
E. Donovan ◽  
M. J. Engebretson ◽  
...  
Keyword(s):  
Solar Wind ◽  
Flow Channel ◽  
Convection Flow ◽  
Transient Effects ◽  
Convection Pattern ◽  
Dayside Magnetopause ◽  
Invaluable Tool ◽  
Magnetospheric Cusp ◽  
Fast Ion ◽  
Global And Local

Abstract. On 14 January 2001, the four Cluster spacecraft passed through the northern magnetospheric mantle in close conjunction to the EISCAT Svalbard Radar (ESR) and approached the post-noon dayside magnetopause over Green-land between 13:00 and 14:00 UT. During that interval, a sudden reorganisation of the high-latitude dayside convection pattern occurred after 13:20 UT, most likely caused by a direction change of the Solar wind magnetic field. The result was an eastward and poleward directed flow-channel, as monitored by the SuperDARN radar network and also by arrays of ground-based magnetometers in Canada, Greenland and Scandinavia. After an initial eastward and later poleward expansion of the flow-channel between 13:20 and 13:40 UT, the four Cluster spacecraft, and the field line footprints covered by the eastward looking scan cycle of the Söndre Strömfjord incoherent scatter radar were engulfed by cusp-like precipitation with transient magnetic and electric field signatures. In addition, the EISCAT Svalbard Radar detected strong transient effects of the convection reorganisation, a poleward moving precipitation, and a fast ion flow-channel in association with the auroral structures that suddenly formed to the west and north of the radar. From a detailed analysis of the coordinated Cluster and ground-based data, it was found that this extraordinary transient convection pattern, indeed, had moved the cusp precipitation from its former pre-noon position into the late post-noon sector, allowing for the first and quite unexpected encounter of the cusp by the Cluster spacecraft. Our findings illustrate the large amplitude of cusp dynamics even in response to moderate solar wind forcing. The global ground-based data proves to be an invaluable tool to monitor the dynamics and width of the affected magnetospheric regions.Key words. Magnetospheric cusp, ionosphere, reconnection, convection flow-channel, Cluster, ground-based observations

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Sign in / Sign up

Export Citation Format

Share Document