@Katie L -

Here's my understanding. 

DÉTACHÉ is usually considered the default bowing stroke if nothing else is notated, this means each note is a smooth bow change - NO pausing, NO stopping, NO lifting the bow.  The bow change does give the illusion of hearing a pause.

We also take into consideration changes may sometimes be necessary if you want to play the strong beats with a down bow.

For your example: BOTH notes are played on the same 'up bow' WITHOUT a deliberate pause or stopping.

• Beamed notes are about rhythm (see phrasing, below). 
• Two beamed eighth notes sound like saying, "One and". 
• There is NO STOPPING, NO LIFTING between the notes, but a lightening of pressure may seem like a slight hesitation/pause while preparing to articulate the 2nd note.  I would NOT go out of my way to make a noticeable 'pause'.
• Articulate the beginning of the 2nd note with your hand/fingers - it only takes a slight squeeze movement to mark the beginning. 

Depending on the type of music played, you might have the option of playing other types of 'double up-bow strokes', like the different ones in this video.

Your example does NOT indicate any 'off string' strokes - so like the cello in this video. 

Phrasing enters the picture when you play like you say it - one way is to use 'Dynamics'. 

• The 1st note in a 'beamed' pair can be considered the START OF A BEAT. 
• 'One' = slightly more emphasis on the 1st note - play a little louder by more weight & bow speed. 
• 'And' = slightly less emphasis on the 2nd note - play slightly softer by less weight & bow speed. 
• BOTH notes are played for the same 'eighth note duration' of time. 

This video shows an example of VIVALDI - about Meter, Beat & Beaming! 

- Emily

@RDP -

I described 2 Up-bow eighth notes - counted 'One', 'And'. 

It's NOT counted 'One', 'And', 'Two' - which describes a different rhythm.

Just like when you play normal Détaché bowing, which is 'Up-bow', 'Down-bow' - it's NOT 'Up-bow', 'Pause', 'Down-bow'. 

If either of the 2 note's time value is cut short, with silence making up for the remainder of it's time - then you are playing Staccato, NOT Détaché (which is the default bowing).  Staccato bowing is notated with a dot above the note(s), in Classical music. 

...I believe you run the risk of crossing a fine timeline, if you set yourself up to think you have to add something - "a pause or stop", between beamed eighth notes or less.  It's important to play smoothly, with intentional phrasing. 

I did NOT describe this as a 'Slur' - there is NO bowing articulation for the 2nd note of a Slur. 

There are also refined forms of Détaché - with different names and characteristics. 

For Double Up-bows in Folk Music, do what fits the genre. 

@RDP -

I NEVER said it wasn't 2 notes. 

Sorry you didn't understand I was trying to describe how the default bowing might be interpreted for this (even though both these notes are the same bowing direction), since nothing specific was notated.

The bottom line - BEAMED notes show a grouping of notes that represent ONE BEAT of rhythm. 

As far as I'm concerned, with nothing specified otherwise, you can bow it however you want to, as long as you don't lose the feeling of that ONE BEAT - it's NOT 2 'beats' of rhythm.

Most importantly, it has now become known that Katie's example is from Vivaldi's "Autumn".  This means I would take the Baroque context into consideration, as well as knowledge that each Concerto of Vivaldi's "Four Seasons" was a rich interpretation of a Sonnet, e.g., animals/birds, people, scenes, and moods - for choosing my bowing.   

Bowing terms, in themselves, can be confusing, so I've started a new thread to dig deeper into that, here:  Interpreting Bowing Notation & Terms Thread