Meteorites & Asteroids

Polarized Microwave Emission From Space Particles In The Upper Atmosphere Of The Earth

By Keith Cowing
Status Report
October 17, 2023
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Polarized Microwave Emission From Space Particles In The Upper Atmosphere Of The Earth
𝐼 and 𝑄 Stokes parameters for silicate grains measured at 220 GHz at the South magnetic pole (top) and at the equator (bottom) aligned with respect to the solar radiation field (π‘˜-alignment). We note that maps at both values of 𝛼 reproduce the spurious patterns seen in the temperature maps in Fig. 6, being the ones in the 𝛼 = βˆ’2.0 due to higher opacities and boundary effects, and the strike patterns seen in the 𝛼 = βˆ’3.5 maps only due to statistical fluctuations in the spatial generation of the photon packages, resulting in negligible spatial variations in the 𝐼 and 𝑄 magnitudes. Maps for the South magnetic pole are identical to those of the equator, since both configurations are equivalent. Negative values of 𝑄 are due to the linear polarization along the π‘Œ axis of the image. — astro-ph.EP

Tons of space particles enter the Earth atmosphere every year, being detected when they produce fireballs, meteor showers, or when they impact the Earth surface.

Particle detection in the showers could also be attempted from space using satellites in low Earth orbit. Measuring the polarization would provide extra crucial information on the dominant alignment mechanisms and the properties of the meteor families. In this article, we evaluate the expected signal to aid in the design of space probes for this purpose.

We have used the RADMC-3D code to simulate the polarized microwave emission of aligned dust particles with different compositions: silicates, carbonates and irons. We have assumed a constant spatial particle density distribution of 0.22 cmβˆ’3, based on particle density measurements carried during meteor showers.

Four different grain size distributions with power indices ranging from βˆ’3.5 to βˆ’2.0 and dust particles with radius ranging from 0.01 ΞΌm to 1 cm have been considered for the simulations. Silicates and carbonates align their minor axis with the direction of the solar radiation field; during the flight time into the Earth atmosphere, iron grains get oriented with the Earth’s magnetic field depending on their size.

Alignment direction is reflected in the Q-Stokes parameter and in the polarization variation along the orbit. Polarization depends on the composition and on the size distribution of the particles. The simulations show that some specific particle populations might be detectable even with a small probe equipped with high sensitivity, photon-counting microwave detectors operating in low Earth orbit.

Jennifer LΓ³pez-Viejobueno, Leire Beitia-Antero, Ana I. GΓ³mez de Castro

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Space Physics (
Cite as: arXiv:2310.08941 [astro-ph.EP](or arXiv:2310.08941v1 [astro-ph.EP] for this version)
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From: Jennifer LΓ³pez-Viejobueno
[v1] Fri, 13 Oct 2023 08:14:49 UTC (6,304 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) πŸ––πŸ»