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2

You seem to be doing dimensional analysis in SI units. The paper seems to using Gaussian units. The magnetic field differs between these units by a factor $c$. In SI units we have $$\mathbf F = q(\mathbf E + \mathbf v \times \mathbf B \tag{SI})$$ but in Gaussian units $$\mathbf F = q(\mathbf E + \frac{\mathbf{v}}{c} \times \mathbf B \tag{G}).$$ The latter ...

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I can only assume that 25 cm of vacuum refers to a vacuum which is at 25 cmHg of pressure. I do think going down to 25 cmHg would mean ~33,330 Pa; that's within the range of a low vacuum.

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While it could represent the pressure of that much water, my first thought is that it is a pressure difference equal to 25 cm of Hg, or 250mmHg. 25cm of water would be a quite weak vacuum. Since it's a vacuum, the internal pressure would be ambient minus that amount. $P_{abs} = 1013mbar + (-333mbar) = 680mbar$

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