Is wake field solver particle beam is run at below specified values?

I am not getting exactly your problem anyways following clarifications
Velocity which you are referring is Beta.
You have not mentioned unit of sigma if it is in mm then mesh size will be very very large as meshing in case of wake filed solver is directly defined by sigma
Even then yes why not wake field solver can be run with this beam definition.

thanks for giving the reply,

in my case i am using sigma in mm (0.001mm) velocity is as beta=0.00006,charge 1e-9, total cavity size is 39mm of radius. here always showing the messagr error like this

"Unable to solve the electrostatic problem for the interface region. Memory for 46925634 mesh points is required, but the maximum number of allowed points is 20000000."

ehat i need to do to solve this problem please suggest me.

I have already mentioned that your sigma is very small which will require hell lot of memory to solve the problem as in wake field solver mesh is defined with reference to sigma of beam.
Error means that you are running out of memory RAM as you require more RAM to solve this problem. To be sure that it has to do all with sigma try to solve the same problem with relaxed sigma like 3mm and see I am sure then you will not get this error. I was also stuck with the same issue as I wanted to simulate for 0.3mm. I am not very sure but with your sigma value I think you will need cluster to solve this problem.
Smaller the value of sigma means denser the mesh which automatically means more RAM and computational resources. Best of LUCK
I am also struggling with the same issue and now I am trying to setup the model with smaller sigma which is realizable with my system and once I will be all sure about the issue then I will use some cluster to simulate for my real problem. Anyways I will discuss the same problem with CST people during conference at Rome tomorrow and will update you if I found some trick or work around.

Hi
Back from the conference unfortunately the answer is es expected as if you go for very short sigma like 0.001 then mesh will be very dense due to frequency attached with beam which you can see in beam properties so you have to use some cluster or work station there is no work around.
Anyways other thing which you can use is if your beam is at the axis of structure then you can use symmetry plans to reduce the total model to 1/4.
Anyways Wake field solver is not fully evolved and CST team is working to improve it. You can generate online ticket to get direct help from CST