What is the purpose of the Parker limit in astroparticle physics experiments?

[HAMJOOP]

I am reading some papers about astroparticle physics and I see something like Parker limit (monopole).

So what is the purpose of setting up this limit ? It is be used to get the expected number of particles per unit area per unit time for later experiments ?

Thanks

 

[Orodruin]

Upper limits typically set a benchmark on how sensitive experiments will have to be in order to actually tell you something you do not already know.