WorkerMonitor directory using excessive disk space

On our Orion server I have found the C:\ProgramData\Solarwinds\JobEngine.v2\ThresholdStreams\WorkerMonitor directory has over 40k files and is taking about 17GB of disk.  The dates on the files start from early this year.  Correlates to about the time we added SAM and our first additional poller.

Does anyone know what they are?  Why they are created?  Can they be suppresses and/or deleted?