I think they plan a nuclear thermal reactor style engine, not plasma.
I'm guessing it's gonna be something like this:
(Russian Nuclear Rocket Engine Design for Mars Exploration)
Abstract: This paper is to promote investigation into the nuclear rocket engine (NRE) propulsion option that
is considered as a key technology for manned Mars exploration. Russian NRE developed since the 1950s in
the former Soviet Union to a full-scale prototype by the 1990s is viewed as advantageous and the most suitable
starting point concept for manned Mars mission application study. The main features of Russian heterogeneous
core NRE design are described and the most valuable experimental performance results are
summarized. These results have demonstrated the significant specific impulse performance advantage of
the NRE over conventional liquid rocket engine (LRE) propulsion technologies. Based on past experience,
the recent developments in the field of high-temperature nuclear fuels, and the latest conceptual studies, the
developed NRE concept is suggested to be upgraded to the nuclear power and propulsion system (NPPS),
more suitable for future manned Mars missions. Although the NRE still needs development for space application,
the problems are solvable with additional effort and funding.
Most of the problems associated with nuclear pollution
hazards are expected to be solved by operating the
NRE only 1000 km above the earth in orbit.
http://qhxb.lib.tsinghua.edu.cn/myweb/e ... 52-260.pdfIt looks as if money will now come.

The nuclear engine for space rockets - seemingly a distant dream of science fiction writers - was, it turns out, not only developed in the top-secret design offices, but also manufactured, and then tested on the proving grounds. "Это была нетривиальная работа", - говорит генеральный конструктор Воронежского федерального государственного предприятия "КБ химавтоматики" Владимир Рачук. "It was a trivial job," - the general designer of the Voronezh Federal State Enterprise "KB Khimavtomatika Vladimir Rachuk. В его устах "нетривиальная работа" означает очень высокую оценку сделанного. In his mouth "non-trivial work" means a very high estimate was made.
(2009.11.09 Added link to the article origin of the picture)