If you are looking to run a virtual machine Junos the options are the vMX and vSRX. If you have a license purchased you get those from the downloads page as noted. If you need a trail version then request them via these pages.
The vSRX on AWS Learning Byte discusses enabling vSRX platform in the Amazon Web Services Wenyu Zhang, Senior Technical Marketing Engineer, demonstrates the Juniper Networks vSRX...
Test drive vMX, vSRX, HealthBot, NorthStar Controller, Contrail Enterprise Multicloud, and much more. What's New. Check out our latest topologies, including: Apstra Automated DC Operations HealthBot - now running v3.1.0, and monitoring routing and security topologies Contrail Enterprise Multicloud with Kubernetes - now running R2008
Jul 29, 2015 · Configure GNS3 Preferences under Virtual Box and load the cloned vSRX virtual machine. Create a simple topology and turn on the devices. Once the vSRX client is up, access it via console and login as root with no password and you're ready to play with Juniper OS.