Plasma distribution in Mercury's magnetosphere derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer observations

Korth, H.; Anderson, B. J.; Gershman, D. J.; Raines, J. M.; Slavin, J. A.; Zurbuchen, T. H.; Solomon, Sean C.; McNutt, R. L.

doi:10.1002/2013ja019567

Cited by 46 publications

(67 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is in agreement with previous observations (e.g. Slavin et al 2010;DiBraccio et al 2013;Korth et al 2014), and shows that the IMF orientation strongly controls the dynamics of the solar wind plasma interaction with Mercury. Figure 10e,f show that the foreshock cavity forms at close distances to Mercury near the south pole during the northward IMF and that it extends to over 6 R M upstream where the size of the perturbed area is comparable to or larger than the size of the planet.…”

Section: Outboundsupporting

confidence: 93%

See 1 more Smart Citation

A modelling approach to infer the solar wind dynamic pressure from magnetic field observations inside Mercury’s magnetosphere

Fatemi

Poirier

Holmström

et al. 2018

A&A

View full text Add to dashboard Cite

Aims. The lack of an upstream solar wind plasma monitor when a spacecraft is inside the highly dynamic magnetosphere of Mercury limits interpretations of observed magnetospheric phenomena and their correlations with upstream solar wind variations. Methods. We used AMITIS, a three-dimensional GPU-based hybrid model of plasma (particle ions and fluid electrons) to infer the solar wind dynamic pressure and Alfvén Mach number upstream of Mercury by comparing our simulation results with MESSENGER magnetic field observations inside the magnetosphere of Mercury. We selected a few orbits of MESSENGER that have been analysed and compared with hybrid simulations before. Then we ran a number of simulations for each orbit (∼30-50 runs) and examined the effects of the upstream solar wind plasma variations on the magnetic fields observed along the trajectory of MESSENGER to find the best agreement between our simulations and observations. Results. We show that, on average, the solar wind dynamic pressure for the selected orbits is slightly lower than the typical estimated dynamic pressure near the orbit of Mercury. However, we show that there is a good agreement between our hybrid simulation results and MESSENGER observations for our estimated solar wind parameters. We also compare the solar wind dynamic pressure inferred from our model with those predicted previously by the WSA-ENLIL model upstream of Mercury, and discuss the agreements and disagreements between the two model predictions. We show that the magnetosphere of Mercury is highly dynamic and controlled by the solar wind plasma and interplanetary magnetic field. In addition, in agreement with previous observations, our simulations show that there are quasi-trapped particles and a partial ring current-like structure in the nightside magnetosphere of Mercury, more evident during a northward interplanetary magnetic field (IMF). We also use our simulations to examine the correlation between the solar wind dynamic pressure and stand-off distance of the magnetopause and compare it with MESSENGER observations. We show that our model results are in good agreement with the response of the magnetopause to the solar wind dynamic pressure, even during extreme solar events. We also show that our model can be used as a virtual solar wind monitor near the orbit of Mercury and this has important implications for interpretation of observations by MESSENGER and the future ESA/JAXA mission to Mercury, BepiColombo.

show abstract

Section: Outboundsupporting

confidence: 93%

“…Consistent with MESSENGER observations (e.g. Schriver et al 2011;Korth et al 2014), our simulations show that this half-ring contains quasi-trapped particles only near the nightside equator that move duskward toward the dayside magnetopause. The quasitrapped particles, also visible in Fig.…”

Section: M1 Flyby: 14 January 2008supporting

confidence: 92%

A modelling approach to infer the solar wind dynamic pressure from magnetic field observations inside Mercury’s magnetosphere

Fatemi

Poirier

Holmström

et al. 2018

A&A

View full text Add to dashboard Cite

show abstract

“…Therefore, to gain insight into EE event systematics and ultimately the underlying physical processes, we have binned the EE event occurrences and associated physical quantities by invariant latitude and magnetic local time (MLT). Invariant latitude [ Korth et al ., ] is the latitude at which a magnetic field line threading the observation point maps onto a sphere of radius R M (where R M is Mercury's radius) centered on Mercury's offset dipole [ Anderson et al ., ]. Magnetic local time is the local time of the EE event location in Mercury solar magnetospheric (MSM) coordinates [ Korth et al ., ].…”

Section: Characteristics Of Ns‐derived Ee Eventsmentioning

confidence: 99%

“…Invariant latitude [ Korth et al ., ] is the latitude at which a magnetic field line threading the observation point maps onto a sphere of radius R M (where R M is Mercury's radius) centered on Mercury's offset dipole [ Anderson et al ., ]. Magnetic local time is the local time of the EE event location in Mercury solar magnetospheric (MSM) coordinates [ Korth et al ., ]. The MSM coordinate system is based on the Mercury solar orbital coordinate system (for which + X points toward the Sun, + Y toward dusk, and + Z toward north) but includes a 479 km offset in the + Z direction.…”

Section: Characteristics Of Ns‐derived Ee Eventsmentioning

confidence: 99%

Comprehensive survey of energetic electron events in Mercury's magnetosphere with data from the MESSENGER Gamma‐Ray and Neutron Spectrometer

et al. 2015

Self Cite

View full text Add to dashboard Cite

Data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Gamma-Ray and Neutron Spectrometer have been used to detect and characterize energetic electron (EE) events in Mercury's magnetosphere. This instrument detects EE events indirectly via bremsstrahlung photons that are emitted when instrument and spacecraft materials stop electrons having energies of tens to hundreds of keV. From Neutron Spectrometer data taken between 18 March 2011 and 31 December 2013 we have identified 2711 EE events. EE event amplitudes versus energy are distributed as a power law and have a dynamic range of a factor of 400. The duration of the EE events ranges from tens of seconds to nearly 20 min. EE events may be classified as bursty (large variation with time over an event) or smooth (small variation). Almost all EE events are detected inside Mercury's magnetosphere on closed field lines. The precise occurrence times of EE events are stochastic, but the events are located in well-defined regions with clear boundaries that persist in time and form what we call "quasi-permanent structures." Bursty events occur closer to dawn and at higher latitudes than smooth events, which are seen near noon-to-dusk local times at lower latitudes. A subset of EE events shows strong periodicities that range from hundreds of seconds to tens of milliseconds. The few-minute periodicities are consistent with the Dungey cycle timescale for the magnetosphere and the occurrence of substorm events in Mercury's magnetotail region. Shorter periods may be related to phenomena such as north-south bounce processes for the energetic electrons.

show abstract

“…The white lines in Figure 11 indicate the modeled boundary between open and closed magnetic field lines (Korth et al, 2014). The majority (97%) of Coincident events occurred within the region of closed magnetic field lines, similar to the results of Lawrence et al (2015).…”

Section: Ee Events: Statistical Analysesmentioning

confidence: 99%

Statistical Study of Mercury's Energetic Electron Events as Observed by the Gamma‐Ray and Neutron Spectrometer Instrument Onboard MESSENGER

et al. 2018

Self Cite

View full text Add to dashboard Cite

We present results from a statistical analysis of Mercury's energetic electron (EE) events as observed by the gamma‐ray and neutron spectrometer instrument onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The main objective of this study is to investigate possible anisotropic behavior of EE events using multiple data sets from MESSENGER instruments. We study the data from the neutron spectrometer (NS) and the gamma‐ray spectrometer anticoincidence shield (ACS) because they use the same type of borated plastic scintillator and, hence, they have very similar response functions, and their large surface areas make them more sensitive to low‐intensity EE events than MESSENGER's particle instrumentation. The combined analysis of NS and ACS data reveals two different classes of energetic electrons: “Standard” events and “ACS‐enhanced” events. Standard events, which comprise over 90% of all events, have signal sizes that are the same in both the ACS and NS. They are likely gyrating particles about Mercury's magnetic field following a 90° pitch angle distribution and are located in well‐defined latitude and altitude regions within Mercury's magnetosphere. ACS‐enhanced events, which comprise less than 10% of all events, have signal sizes in the ACS that are 10 to 100 times larger than those observed by the NS. They follow a beam‐like distribution and are observed both inside and outside Mercury's magnetosphere with a wider range of latitudes and altitudes than Standard events. The difference between the Standard and ACS‐enhanced event characteristics suggests distinct underyling acceleration mechanisms.

show abstract

Plasma distribution in Mercury's magnetosphere derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer observations

Cited by 46 publications

References 59 publications

A modelling approach to infer the solar wind dynamic pressure from magnetic field observations inside Mercury’s magnetosphere

A modelling approach to infer the solar wind dynamic pressure from magnetic field observations inside Mercury’s magnetosphere

Comprehensive survey of energetic electron events in Mercury's magnetosphere with data from the MESSENGER Gamma‐Ray and Neutron Spectrometer

Statistical Study of Mercury's Energetic Electron Events as Observed by the Gamma‐Ray and Neutron Spectrometer Instrument Onboard MESSENGER

Contact Info

Product

Resources

About