How does a python thread work?

[jackbk]

I have used Python thread so far, but I had a question that I can not find an answer by myself.
Google some related information, but I do not satisfy with this. Do you have any experience with this?

I have a thread as below (file name test_thread.py)

import time

def AThread(aEvent):
   while True:
       aEvent.wait()
       aEvent.clear()
       print "aEvent set already"

aEvent  = threading.Event()
AThread = threading.Thread(name='AThread', 
                      target=AThread,
                      args=(aEvent,))
try:
   AThread.start()
except:
   print "Can not start AThread"

time.sleep(5)
aEvent.set()

I have a thread named "AThread". This thread must wait for "aEvent" until "aEvent" is set.
When I run this thread on Linux by invoking python test_thread.py, after 5 seconds, message "aEvent set already" is printed.
After that, there is nothing because aEvent is set once in my program. It is normal.

However, I want to know the below.
1. If I stop the test_thread.py by pressing Ctrl+C or Ctrl+Z, is the AThread really killed?
I am not confident to say AThread is killed because test_thread.py still occur when I use "top" command on Linux terminal.

2. Is there any way to "stop" the thread? Where should we put a "stop" method to stop the thread in test_thread.py?
Because I see we call "start()" method to start the thread, but there is no method to "stop" the thread.
I see there is "join()" method can terminate a thread but I do not understand how to use it.