<h2> ULYSSES SWOOPS Proton Temperature </h2>
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    The proton temperature has been estimated in two different ways, one of which
will sometimes lead to an overestimate of the temperature and one of which will
sometimes lead to an underestimate. T-large is the integral of the distribution
in three-dimensional velocity space over all energy channels and angle bins
that are statistically above noise. The criterion for noise determination is
based upon the estimation of the total contribution from a shell that is
spherically symmetric in velocity space. T-large has the drawback that at
times when the solar wind is cold the angular responses of the instrument
channels are as wide or wider than the beam, and the temperature is
overestimated. T-small is estimated by summing over angle the observations at a
fixed energy. The moments of the resulting one dimensional plasma spectrum are
then summed and the resulting RR (radial) component of the temperature tensor
is used as the estimate of proton temperature. Additionally, to avoid
contamination from alpha particles, no channels further in velocity space from
the proton peak than the minimum in flux between the proton and alpha particles
peaks are used in the T-small estimate. T-large and T-small will generally
bracket the true temperature. However, for very cold plasma, T-small may not be
a true minimum.

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