Upl

multiples of single groin magnetic moment

Figure 1. Measured magnetic dipole moments of individual grains. The data has been normalized with the nominal value ¡/z[ « 3 • 10-13 Am2. Errors apply to all the data.

solar nebula as a result of various melting processes [9,10]. Potentially magnetic minerals such as magnetite, phyrrotite, and iron-nickel have been detected in meteoritic samples [11] and in comet P/Halley's dust [12]. Together with the strong nebular magnetic fields that are inferred from the paleomagnetic record in meteorites [11], this should have produced a population of magnetized dust grains.

The long-ranged interactions between magnetized dust grains are responsible for an enhanced collisional cross section a for these particles, thus inducing a selective growth mechanism together with an acceleration of the coagulation process itself. Numerical simulations by Niibold and Glassmeier [13] and Niibold, Dominik, and Glassmeier [14] have been able to quantify this enhancement. As has been shown experimentally by Nuth et al. [9], magnetic dust aggregation creates web-like structures that could act as 'fishing nets' for nonmagnetic particles. This could serve as a starting point for rapid grain growth and new compositional features [13]. Ideally dipolar interactions between magnetized grains lead to elongated structures that could explain interstellar polarization of starlight (e.g. [15]) and may have been found in meteoritic samples [8]. As an experimental test for these considerations we performed analogous experiments with magnetized micron-sized dust grains. In this paper, we will report on first results and future perspectives.

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