Mars surface
Mumbai: Various plasma waves are often observed in the Earth’s magnetosphere, a magnetic field cavity around the Earth. In general, plasma waves are identified as the short-time scale fluctuations in the electric and magnetic field observations. These plasma waves play an important role in the energization and transport of the charged particles in the Earth’s magnetosphere. Some of the plasma waves like electromagnetic ion cyclotron waves act as a cleaning agent for the Earth’s radiation belt, which is hazardous to our satellites.
Knowing this scenario, researchers are curious to understand the existence of various plasma waves in the vicinity of unmagnetized planets like Mars. The planet Mars does not have any intrinsic magnetic field therefore the high-speed solar wind coming from the Sun interacts directly with the Mars atmosphere, like an obstacle in the flow.
The detection of the existence of high-frequency plasma waves in the Martian Upper Atmosphere with novel narrowband and broadband features can help understand plasma processes in the Martian plasma environment.
The researchers at the Indian Institute of Geomagnetism (IIG) examined the existence of high-frequency plasma waves in the Martian plasma environment by making use of the high-resolution electric field data from the Mars Atmosphere and Volatile Evolution Mission (MAVEN) spacecraft of NASA. These waves could be either electron oscillations that propagate parallel to the background magnetic field (Langmuir waves) or electron oscillations that propagate perpendicular to the background magnetic field (upper-hybrid type waves) in the magnetosheath region of Mars.
They observed two distinct wave modes with frequency below and above the electron plasma frequency in the Martian magnetosphere. These waves were observed around 5 LT (local time) on February 9, 2015, when the MAVEN spacecraft crossed the magnetopause boundary and entered the magnetosheath region. These waves are either broadband- or narrowband-type with distinguishable features in the frequency domain. The broadband waves were consistently found to have periodic patchy structures with a periodicity of 8–14 milliseconds.
Observations of such waves provide a tool to explore how electrons gain or dissipate energy in the Martian plasma environment. The physical mechanism responsible for the generation of broadband-type waves and its modulation remains unexplained and further investigation is required. This study was carried out by IIG scientists in collaboration with scientists from Japan, USA, and UAE and it has been published in the Astronomy & Astrophysics Journal.
– global bihari bureau
