Nanodust Detection between 1 and 5 AU Using Cassini Wave Measurements

• The solar system contains solids of all sizes, ranging from kilometer-sized bodies to nano-sized particles. Nanograins have been detected in situ in the Earth's atmosphere, near cometary and giant planet environments, and more recently in the solar wind at 1 AU. The. latter nanograins are thought to be formed in the inner solar system dust cloud, mainly through the collisional break-up of larger grains, and are then picked up and accelerated by the magnetized solar wind because of their large charge-to-mass ratio. In the present paper, we analyze the low frequency bursty noise identified in the Cassini radio and plasma wave data during the spacecraft cruise phase inside Jupiter's orbit. The magnitude, spectral shape, and waveform of this broadband noise are. consistent with the signatures of the nano particles that traveled. at solar wind speed. and. impinged. on the spacecraft surface. Nanoparticles were observed whenever the radio instrument was turned on and able to detect them. at different heliocentric distances between Earth and Jupiter, suggesting their ubiquitous presence in the heliosphere. We analyzed the radial dependence of the nanodust flux with heliospheric distance and found that it is consistent with the dynamics of nanodust originating from the inner heliosphere and picked. up by the solar wind. The contribution of the nanodust produced in the asteroid belt appears to be negligible compared to the trapping region in the inner heliosphere. In contrast, further out, nanodust is. mainly produced by the volcanism of active moons such as Io and Enceladus.

Subject headings

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Keyword

interplanetary medium

Sun: heliosphere

Publication and Content Type

ref (subject category)

art (subject category)