Plasma entities, known as magnetosheath jets, with higher dynamic pressure than the surrounding plasma, are often seen at Earth. They generate waves and contribute to energy transfer in the magnetosheath. Affecting the magnetopause, they cause surface waves and transfer energy into the magnetosphere, causing throat auroras and magnetic signatures detectable on the ground. We show that jets exist also beyond Earth’s environment in the magnetosheath of Mars, using data obtained by the MAVEN spacecraft. Thus, jets can be created also at Mars, which differs from Earth by its smaller bow shock, and they are associated with an increased level of magnetic field fluctuations. Jets couple large and small scales in magnetosheaths in the solar system and can play a similar part in astrophysical plasmas.

Magnetosheath jets are localized dynamic pressure enhancements in the magnetosheath. We make use of the high time resolution burst mode data of the Magnetospheric Multiscale mission for an analysis of waves in plasmas associated with three magnetosheath jets. We find both electromagnetic and electrostatic waves over the frequency range from 0 to 4 kHz that can be probed by the instruments on board the MMS spacecraft. At high frequencies we find electrostatic solitary waves, electron acoustic waves, and whistler waves. Electron acoustic waves and whistler waves show the typical properties expected from theory assuming approximations of a homogeneous plasma and linearity. In addition, 0.2 Hz waves in the magnetic field, 1 Hz electromagnetic waves, and lower hybrid waves are observed. For these waves the approximation of a homogeneous plasma does not hold anymore and the observed waves show properties from several different basic wave modes. In addition, we investigate how the various types of waves are generated. We show evidence that, the 1 Hz waves are connected to gradients in the density and magnetic field. The whistler waves are generated by a butterfly‐shaped pitch‐angle distribution and the electron acoustic waves by a cold electron population. The lower hybrid waves are probably generated by currents at the boundary of the jets. As for the other waves we can only speculate about the generation mechanism due to limitations of the instruments. Studying waves in jets will help to address the microphysics in jets which can help to understand the evolution of jets better.

<p><span dir="ltr" role="presentation">The magnetosheath is a region downstream of the bow shock filled with turbulent, deceler</span><span dir="ltr" role="presentation">ated solar wind plasma which is flowing earthwards.</span> <span dir="ltr" role="presentation">This solar wind flow sometimes shows</span> <span dir="ltr" role="presentation">signatures of localized structures with enhanced dynamic pressure, so called magnetosheath </span><span dir="ltr" role="presentation">jets. These jets are often  associated with low angles between the bow shock normal and the </span><span dir="ltr" role="presentation">interplanetary magnetic field (IMF) direction, the so called quasi-parallel bow shock.</span> <span dir="ltr" role="presentation">Less </span><span dir="ltr" role="presentation">often they are also found behind the quasi-perpendicular bow shock.</span></p> <p><br role="presentation" /><span dir="ltr" role="presentation">As jets propagate through the magnetosheath, they interact with the surrounding plasma. </span><span dir="ltr" role="presentation">Studying waves inside, and in the vicinity of, jets is a step towards understanding the interact</span><span dir="ltr" role="presentation">ion of jets with the surrounding plasma. So far whistler waves, electrostatic waves, waves in </span><span dir="ltr" role="presentation">the lower hybrid frequency range as well as low frequency waves have been reported. However, </span><span dir="ltr" role="presentation">the sources of these waves are unknown. In addition, further types of waves may be associated </span><span dir="ltr" role="presentation">with the jets.</span></p> <p><br role="presentation" /><span dir="ltr" role="presentation">We conduct a study on waves in magnetosheath jets using burst mode data of the Magneto</span><span dir="ltr" role="presentation">spheric Multiscale (MMS) mission. The magnetic and electric field data are provided with a</span> <span dir="ltr" role="presentation">sampling rate of 8 kHz, while previous studies used data sets with much lower sampling rates. </span><span dir="ltr" role="presentation">The high time resolution allows us to study different waves over a large frequency range and </span><span dir="ltr" role="presentation">investigate properties of these waves. In addition, we discuss possible generation mechanisms.</span></p>