2D Arrow Surface Plot -- Arrow Length Logarithmic

Hello,

I am plotting a 2D Surface with an arrow surface. I need to scale my arrows logarithmically, but I am unsure whether this scaling is a natural logarithm or a base 10 logarithm. Which is it? The COMSOL Multiphysics User Guide states:

"Logarithmic, so that the length of the arrows is proportional to the logarithm of the
magnitude of the quantity they represent. This makes arrows representing small
values relatively larger. The value in the Range quotient field (default: 100)
determines the ratio between the smallest and largest values in the range of values
for the logarithmic arrow length."

If this is a natural logarithm, is there any way that I can scale my arrows with a base 10 logarithm? I will have some negative values in my vectors, so taking a log10 before plotting is not an option.

Thanks,
Lauren