Plasma engine?

[juliemac]

How does the engine work?<br /><br />http://edition.cnn.com/2006/TECH/space/07/20/costa.rica.rockets.reut/index.html

 

[harmonicaman]

It works very well; at least theoretically...<br /><br />VASIMR scematic.

 

[juliemac]

Good image. Simple design by the looks. I understand most of the design, but have a few q's<br />1) The helicon antenna. How does it elevate the energy level to plasma from a gas?<br />2) Where does the motor get the DC energy required to squeeze and control the plasma beam if it were used in a space craft?

 

[vogon13]

Exhaust from VASIMIR may loop around and contact vehicle. (no one knows for sure)<br /><br />If it does, it will negate the thrust partially (or worse).<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[qso1]

IIRC, there are three cells in the VASIMR rocket.<br /><br />The forward cell is where hydrogen or some other fuel is ionized and becomes plasma.<br /><br />A central cell further heats the plasma through electromagnetic energy in the form of radio waves. The process is similar to how a microwave oven works. <br /><br />The aft cell takes the plasma through a magnetic nozzle and exhausts it at high velocity. This magnetic nozzle is what keeps the plasma from destroying the craft theoretically. At the temperature of plasma (100 million F plus), anything the plasma contacts would be vaporized.<br /><br />Plasma propulsion offers ISPs of between 10,000 and 200,000 IIRC. Its theoretical at this point as to what ISP will be possible but the range of ISP is where VASIMR gets its name...VAriable Specific Impulse Magnetoplasma Rocket. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[juliemac]

I googled the subject and learned a lot. The magnetic feilds need to contain the plasma as well as the miocrowave energy to super heat the plasma, will take a huge amount of energy.<br />Loss of this power would rupture the containment field, but the plasma would cool quickly.<br /><br />What would you use as an electrical power source? A closed loop nuke/steam system? Its all I can think of that would generate the MW's needed.

 

[qso1]

I don't recall what the power source was to have been. It would seem a closed loop nuclear steam system would be redundant. May as well go NTR if one is going to need a nuclear reactor steam producing power system just to generate power for another nuclear plasma generation system.<br /><br />But like I said, I don't know all the particulars. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>