From: daellis94@gmail.com   
      
   On Thursday, May 24, 2018 at 9:53:20 AM UTC-4, eripe wrote:   
   > On Wednesday, May 23, 2018 at 2:08:14 AM UTC+7, David Ellis wrote:   
   > > So, I'm hoping someone here knows enough about how lasers function to give   
   me some helpful pointers.     
   > >    
   > > I'm doing some thinking on a science-fictional space warship that would   
   utilize a mix of rail-guns and missiles for ship-versus-ship engagements, and   
   rely on lasers for its missile defense needs.     
   > >    
   > > I recently did a bit more in-depth reading on the ever-useful Atomic   
   Rockets website to try and get a sense for what I would want out of a laser   
   used for such applications.  My general idea is to use a phased-array,   
   near-ultraviolet laser (I settled    
   on a wavelength of around 250 nanometers, because why not) that would deliver   
   energy in a series of microsecond pulses at a rate of four pulses every   
   second.     
   > >    
   > > My hope is to justify a laser that could deliver energy at a rate   
   sufficient to cause impulsive shock effects in steel at a range of 500   
   kilometers.  This is partly a goal, and partly a starting base-line for my own   
   calculations.  As a base-line, I    
   was also thinking of average power consumption comparable to the ~5 megawatt   
   chemical oxygen-iodine laser used on the Air Force's YAL-1 prototype.     
   > >    
   > > I calculated the power required to vaporize steel at a rate that would   
   exceed the velocity of sound in steel, and tried to work back from there using   
   Atomic Rockets's laser equations, treating the phased-array laser as a unitary   
   laser system with a 2.   
   5-meter lens.     
   > >    
   > > If I take the energy of a one-second beam at 5 megawatts and divide it   
   into fourths, and take each of those four pulses and compress it into a one   
   microsecond period of time, the energy delivery of a diffraction-limited laser   
   would appear to require    
   only a little over 3 megawatts (average beam power, this is, not peak pulse   
   power), but adjusting the numbers to account for a beam with an arbitrary   
   quality of 3, the average power needed was between 28 and 29 megawatts.     
   > >    
   > > Now, working out how much beam power is more than I want to provide is   
   easy enough.  I simply have no real basis for knowing or understanding what   
   kind of beam quality makes sense for a laser of a particular power, size,   
   etc.  I also don't know how    
   to relate the quality of phased-array beam to that of a conventional beam in   
   any reasonably believable terms.     
   > >    
   > > Another problem is that I have no idea whether I am understanding pulsed   
   lasers correctly.  Is compressing a fourth of a second of energy into a   
   microsecond pulse even something a designer would have the freedom to do?  Do   
   pulsed lasers work like    
   that?     
   > >    
   > > Hopefully there is someone here that understands lasers better than I do.   
   >    
   > I cant answer your question. Just want to recommend this blog, and his game.   
   >    
   > https://childrenofadeadearth.wordpress.com/   
      
   CoaDE is a wonderful game.  I have enjoyed it for quite some time, now.  It,   
   together with Atomic Rockets, have done quite a lot for my grasp of how   
   various weapon types might be applied in an exo-atmospheric setting.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)