Charged particle environment of Titan during the T9 flyby

The ion measurements of the Cassini Plasma Spectrometer are presented which were acquired on 26 December 2005, during the T9 flyby at Titan. The plasma flow and magnetic field directions in the distant plasma environment of the moon were distinctly different from the other flybys. The near-Titan environment, dominated by ions of Titan origin, had a split signature, each with different ion composition; the first region was dominated by dense, slow, and cold ions in the 16-19 and 28-40 amu mass range, the second region contained only ions with mass 1 and 2, much less dense and less slow. Magnetospheric ions penetrate marginally into region 1, whereas the region-2 ion population is mixed. A detailed analysis has led us to conclude that the first event was due to the crossing of the mantle of Titan, whereas the second one very likely was a wake crossing. The split indicates the non-convexity of the ion-dominated volume around Titan. Both ion distributions are analysed in detail

Ionospheric electrons in Titan's tail: Plasma structure during the cassini T9 encounter

We present results from the CAPS electron spectrometer obtained during the downstream flyby of Titan on 26 December 2005, which occurred during a period of enhanced plasma pressure inside the magnetosphere. The electron data show an unusual split signature with two principal intervals of interest outside the nominal corotation wake. Interval 1 shows direct evidence for ionospheric plasma escape at several RT in Titan's tail. Interval 2 shows a complex plasma structure, a mix between plasma of ionospheric and magnetospheric origin. We suggest a mechanism for plasma escape based on ambipolar electric fields set up by suprathermal ionospheric photoelectrons

Cassini encounters with hot flow anomaly-like phenomena at Saturn's bow shock

Crossings of Saturn´s magnetopause made by the Cassini spacecraft on 12, 13 and 17 March 2006 are analysed. During this period Cassini´s trajectory was approximately parallel to the magnetopause boundary given by a model of the surface. Magnetic field and electron data are used to identify excursions into the magnetosheath bounded by crossings of the magnetopause current layer. Minimum variance analysis of the magnetic field vector measurements is used to determine the normal to the boundary for each crossing. The normals corresponding to the crossings oscillate about an average orientation that is consistent with the unperturbed normal predicted by the surface model. This reveals the presence of regular boundary waves with a direction of propagation found to be within 24° of Saturn´s rotational equator. Two categories of boundary wave are identified: the first with a period of the order of hours, and the second with a period of 45±9 min. Based on the propagation direction and a comparison of magnetospheric and magnetosheath magnetic fields, we conclude that both types of wave were driven by the Kelvin-Helmholtz instability. The observed boundary perturbations are consistent with a superposition of different types of surface wave activity.Fil: Masters, A.. Imperial College London; Reino UnidoFil: Arridge, C. S.. University College London; Estados UnidosFil: Dougherty, M. K.. Imperial College London; Reino UnidoFil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Billingham, L.. Imperial College London; Reino UnidoFil: Schwartz, S. J.. Imperial College London; Reino UnidoFil: Jackman, C. M.. Imperial College London; Reino UnidoFil: Bebesi, Z.. Research Institute for Particle and Nuclear Physics; HungríaFil: Coates, A. J.. University College London; Estados UnidosFil: Thomsen, M. F.. Los Alamos National Laboratory; Estados Unido

BepiColombo’s Cruise Phase: Unique Opportunity for Synergistic Observations

The investigation of multi-spacecraft coordinated observations during the cruise phase of BepiColombo (ESA/JAXA) are reported, with a particular emphasis on the recently launched missions, Solar Orbiter (ESA/NASA) and Parker Solar Probe (NASA). Despite some payload constraints, many instruments onboard BepiColombo are operating during its cruise phase simultaneously covering a wide range of heliocentric distances (0.28 AU–0.5 AU). Hence, the various spacecraft configurations and the combined in-situ and remote sensing measurements from the different spacecraft, offer unique opportunities for BepiColombo to be part of these unprecedented multipoint synergistic observations and for potential scientific studies in the inner heliosphere, even before its orbit insertion around Mercury in December 2025. The main goal of this report is to present the coordinated observation opportunities during the cruise phase of BepiColombo (excluding the planetary flybys). We summarize the identified science topics, the operational instruments, the method we have used to identify the windows of opportunity and discuss the planning of joint observations in the future

BepiColombo's Cruise Phase : Unique Opportunity for Synergistic Observations

The investigation of multi-spacecraft coordinated observations during the cruise phase of BepiColombo (ESA/JAXA) are reported, with a particular emphasis on the recently launched missions, Solar Orbiter (ESA/NASA) and Parker Solar Probe (NASA). Despite some payload constraints, many instruments onboard BepiColombo are operating during its cruise phase simultaneously covering a wide range of heliocentric distances (0.28 AU-0.5 AU). Hence, the various spacecraft configurations and the combined in-situ and remote sensing measurements from the different spacecraft, offer unique opportunities for BepiColombo to be part of these unprecedented multipoint synergistic observations and for potential scientific studies in the inner heliosphere, even before its orbit insertion around Mercury in December 2025. The main goal of this report is to present the coordinated observation opportunities during the cruise phase of BepiColombo (excluding the planetary flybys). We summarize the identified science topics, the operational instruments, the method we have used to identify the windows of opportunity and discuss the planning of joint observations in the future.Peer reviewe

BepiColombo’s Cruise Phase: Unique Opportunity for Synergistic Observations

The investigation of multi-spacecraft coordinated observations during the cruise phase of BepiColombo (ESA/JAXA) are reported, with a particular emphasis on the recently launched missions, Solar Orbiter (ESA/NASA) and Parker Solar Probe (NASA). Despite some payload constraints, many instruments onboard BepiColombo are operating during its cruise phase simultaneously covering a wide range of heliocentric distances (0.28 AU–0.5 AU). Hence, the various spacecraft configurations and the combined in-situ and remote sensing measurements from the different spacecraft, offer unique opportunities for BepiColombo to be part of these unprecedented multipoint synergistic observations and for potential scientific studies in the inner heliosphere, even before its orbit insertion around Mercury in December 2025. The main goal of this report is to present the coordinated observation opportunities during the cruise phase of BepiColombo (excluding the planetary flybys). We summarize the identified science topics, the operational instruments, the method we have used to identify the windows of opportunity and discuss the planning of joint observations in the future.</p

Ion distributions of different Kronian plasma regions

Plasma data from the Cassini Plasma Spectrometer experiment were used to investigate the properties of the variable plasma environment of Titan's orbit. The characteristics of this plasma environment play a crucial role in the plasma-moon interaction and also have a strong influence on the ionosphere of Titan. Using dynamic energy spectra of ions within +/- 3 h of the Titan flybys we identified different ambient plasma environments, similar to the ones proposed earlier based on electron measurements. Expanding the time interval to 12 h to cover full SKR periods, and taking into account the composition of the ions, we showed that the longer intervals include all the previous categories, and a special one, a short event, rich in heavy ions. Detailed study of the vicinity of these events revealed the fine structure of the magnetodisk of Saturn, having a narrow central sheet of very high heavy ion content, heavy rich events occurring when the spacecraft crosses this central sheet. We also proved that the heavy rich events appear periodically in longitude, but with a period slightly (by 0.35 degrees/day) longer than the SLS3 period