From: Amara Graps (Amara.Graps@mpi-hd.mpg.de)
Date: Sat Jan 20 2001 - 08:39:05 MST
From: "J. R. Molloy" <jr@shasta.com>, Fri, 19 Jan 2001
>From: "scerir" <scerir@libero.it>
>> * How do cosmic accelerators work and what are they accelerating?
Cosmic particle and cosmic ray accelerators both?
(No cosmic dust accelerators, right Amara? ^t^^t )
^^^^^^^^^^^^^^^^^^^^^^^^
untrue
Until last summer there were two dust accelerators in the world:
one in Canterbury (University of Kent), and one here in this
institute (MPI-K, Heidelberg). Then the Canterbury group split and
moved, and I'm not sure anymore if that lab is finished.
So then, let's say for the moment, I'm working at the place that
has the last remaining dust accelerator in the world.
Think about it.. Would scientists want to send dust instruments into
space without proper lab work? How do you think the HEOS, Helios,
Ulysses, Cassini, Galileo, Gorid, Stardust, etc dust detectors were
calibrated ...? (answer: here at the dust accelerator)
It's not a great accelerator, and about >40 years old (however well
maintained and upgraded) and the fastest we've so far been able to
accelerate the grains (mostly iron: the particles must be able to
easily carry a charge) is to about 10 km/sec. However the other PhD
student (besides me) in our group has successfully rebuilt part of
the acclerator to accelerate some new kinds of particles (latex),
which carry a good charge and can accelerate faster. We would like to
ideally have .1 micron and smaller particles be accelerated to greater
than 50 km/sec.
(and the universe is what it is, and our technology isn't good enough
in some cases.. the Jovian dust streams have speeds of > 300km/sec and
sizes ~1 nanometer, and therefore outside of the calibration of our
spacecraft dust detectors.)
Amara
Amara
--
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Amara Graps | Max-Planck-Institut fuer Kernphysik
Interplanetary Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY
Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps
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"Never fight an inanimate object." - P. J. O'Rourke
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