BepiColombo is a joint mission between the European Space Agency, ESA, and the Japanese Aerospace Exploration Agency, JAXA, to perform a comprehensive exploration of Mercury. Launched on
20
th
...October 2018 from the European spaceport in Kourou, French Guiana, the spacecraft is now en route to Mercury.
Two orbiters have been sent to Mercury and will be put into dedicated, polar orbits around the planet to study the planet and its environment. One orbiter, Mio, is provided by JAXA, and one orbiter, MPO, is provided by ESA. The scientific payload of both spacecraft will provide detailed information necessary to understand the origin and evolution of the planet itself and its surrounding environment. Mercury is the planet closest to the Sun, the only terrestrial planet besides Earth with a self-sustained magnetic field, and the smallest planet in our Solar System. It is a key planet for understanding the evolutionary history of our Solar System and therefore also for the question of how the Earth and our Planetary System were formed.
The scientific objectives focus on a global characterization of Mercury through the investigation of its interior, surface, exosphere, and magnetosphere. In addition, instrumentation onboard BepiColombo will be used to test Einstein’s theory of general relativity. Major effort was put into optimizing the scientific return of the mission by defining a payload such that individual measurements can be interrelated and complement each other.
The self-consistently generated current-free electric double layer (DL) is shown to scale up with the source tube diameter and appears not to be affected by rf driving frequency and changes in ...reactor geometry. This Letter presents the first simultaneous measurements of local plasma potential and beam energy as a function of axial position. The DL is shown to be no more than 5 mm thick (20 D lengths) and positioned just downstream of the maximum in the magnetic field gradient. Furthermore, its position relative to the magnetic field is observed to be invariant as the magnetic field is translated axially. Measurements of the potential drop across the DL are presented for pressures down to 0.09 mTorr and the DL strength (phiDL/T(e)) is determined to be between 5 and 7.
Ion cyclotron waves at approximately 0.7 the ion gyrofrequency have been observed experimentally in the large volume helicon reactor WOMBAT. These waves are highly localized along the axis of the ...device where a 8 cm diameter, 2 m long. Ar II plasma column is produced. Spectral measurements reveal a four-wave interaction where energy is down-converted to the ion cyclotron mode from the helicon pump. The experimental results are explained in terms of a filamentation type instability.
A prototype of the helicon double layer thruster (HDLT) is designed and manufactured. Initial tests with the thruster mounted on a small vacuum chamber (pumping speed of 700 l ldr s -1 ) show ...successful operation in xenon with the formation of the double layer which generates a low divergence ion beam, which is the source of thrust. The prototype is subsequently inserted inside a much larger space simulation chamber (pumping speed of 7000 l ldr s -1 ). A high-density blue mode is found when increasing the RF power above 380 W, and measurements with a Langmuir probe give an estimated density of 10 12 cm -3 in the thruster. An image of the HDLT operating in the high-density blue mode is presented.
The article examines the origins and development of the ethnocentrism notion. The author expounds her views of the content, structure, forms, and manifestations of this social-psychological ...phenomenon.
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