For example, within the first few months of its operation in 2019, the orbiter provided the Moon's sharpest image ever taken, detected the element Argon-40, provided illuminated images of the Moon, performed 3D mapping of the Moon’s surface, and detected charged particles and their intensity variations from the solar wind. The Chandrayaan-2 mission is believed to be 95-98% successful due to precise mission management that has ensured a long life for the orbiter. But the Orbiter-which forms a significant chunk of the mission-carried eight scientific instruments on board and continues to successfully collect and relay crucial insights about the Moon to date. Unfortunately, the Lander crashed on the Moon’s surface while attempting to make a soft landing.

Geometry of the interaction between fast solar wind and ambient solar wind.In July 2019, the Indian Space Research Organisation (ISRO) launched Chandrayaan-2, and nearly a month later, on August 20, 2019, the historic lunar mission spacecraft entered the lunar orbit. When this compressed solar wind boundary has passed Earth, we will see that the solar wind speed starts to increase while the total strength (Bt) of the interplanetary magnetic field and the solar wind density decreases. This phenomenon is often referred to as a Stream Interaction Region (SIR) or as a Co-rotating Interaction Region (CIR) and is almost always associated with an increase in the total strength (Bt) of the interplanetary magnetic field. This increase of the solar wind density occurs because the faster solar wind bunches up the slower solar wind particles in front of it. Other than a coronal mass ejection, a coronal hole high speed stream (CH HSS) arrives slowly with first a steady increase in the solar wind density over the course of a couple of hours. How do I recognize a coronal hole stream? Coronal holes can also develop in isolation from the polar coronal holes which is more common in the years just before and after solar minimum. Coronal holes often persist for weeks or months and change in shape and size as time goes by. These extensions towards lower latitudes can sometimes disconnect from the polar coronal hole and become an isolated structure by itself. Only if these coronal holes grow and expand towards lower latitudes we sometimes experience the high speed solar wind flow coming from these polar coronal holes. The coronal holes at the solar poles are the most stable especially in the years around solar minimum but they rarely influence our planet.

Coronal holes are usually not interesting for aurora watchers at the middle latitudes and only occasionally cause geomagnetic storm conditions.Ĭoronal holes can develop at any time and location on the Sun. Large coronal holes often result in faster solar wind than smaller coronal holes. Depending on the size and location of the coronal hole on the disk, more or less auroral activity can be expected. When a coronal hole is positioned near the centre of the Earth-facing solar disk, these hot gases flow towards Earth at a higher speed than the regular solar wind and cause geomagnetic disturbances on Earth with enhanced auroral activity. Instead of keeping the hot gas together, these open magnetic field lines cause a coronal hole to form, where solar wind can escape at high speeds. At the moment we do not yet know where they reconnect. Instead of returning to the surface, these magnetic field lines stay open and stretch out into space. The magnetic field of a coronal hole is different than the rest of the Sun. Coronal holes are thus not literal holes in the Sun, it is just kind of looks like it in certain extreme ultraviolet wavelengths! A typical coronal hole as seen by NASA’s Solar Dynamics Observatory. These areas are characterized by much lower temperatures and lower densities compared to their surroundings which make coronal holes appear dark. The dark and empty looking areas are places where the magnetic field of the Sun reaches into space so that these hot gases can escape. The bright areas on these images show us hot and dense gas that is captured by the magnetic field of the Sun. The magnetic field of the Sun plays an important role in terms of what we see on these images. This outermost layer of the Sun is called the corona. When we look at solar imagery from NASA's Solar Dynamics Observatory (SDO) in extreme ultraviolet at a wavelength of 193 or 211 Ångström, we can see the hot outer layers of the Sun's atmosphere.

Gas of sun corona