Title:   Voyager-1 beyond the Heliopause:  Lessons and Challenges

In August 2012, the Voyager-1 reached a new milestone and entered a new world: 
the plasma density increased dramatically,  anomalous cosmic rays disappeared 
while the flux of galactic cosmic rays (GCRs) settled to a new, higher level 
and remained nearly  constant since then. The magnetic field  has  shown little 
fluctuations. There is a broad, though not univocal consensus that Voyager-1 
crossed the Heliopause and entered the interstellar medium. The colloquium will 
discuss some of the new challenges brought by the new results. The question arose 
if the present flux of galactic cosmic rays corresponds to the undisturbed GCR 
flux in the local interstellar medium or further modulation should be expected beyond 
the Heliopause. In addition, GCR intensities also showed small transient increases 
"bumps" which lasted a couple of weeks and were followed by plasma oscillations. 
These unexpected  events were most likely caused by disturbances generated at the 
Sun and propagating into the interstellar medium. We shall overview the possible 
interpretations and the lesson learned from these events. The global structure of 
the heliosphere is still debated. We shall discuss how cosmic rays can help to 
decide between the currently competing ideas.