It doesn't look like there is an obvious download link (or I'm too dumb to locate it). b̶u̶t̶ ̶y̶o̶u̶ ̶c̶a̶n̶ ̶g̶r̶a̶b̶ ̶a̶n̶ ̶i̶m̶a̶g̶e̶ ̶f̶r̶o̶m̶ ̶h̶e̶r̶e̶:̶ ̶h̶t̶t̶p̶s̶:̶/̶/̶d̶o̶w̶n̶l̶o̶a̶d̶.̶h̶a̶i̶k̶u̶-̶o̶s̶.̶o̶r̶g̶/̶n̶i̶g̶h̶t̶l̶y̶-̶i̶m̶a̶g̶e̶s̶/̶r̶i̶s̶c̶v̶6̶4̶/̶ Please refer to waddlesplash's reply.

I guess you can try it on Qemu. Might test it later. UTM offers "Risc-V Spike board" among others.